# -*- coding: utf-8 -*- # Copyright 2014, 2015 OpenMarket Ltd # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """This layer is responsible for replicating with remote home servers using a given transport. """ from twisted.internet import defer from .units import Transaction, Edu from .persistence import TransactionActions from synapse.util.logutils import log_function from synapse.util.logcontext import PreserveLoggingContext from synapse.events import FrozenEvent import logging logger = logging.getLogger(__name__) class ReplicationLayer(object): """This layer is responsible for replicating with remote home servers over the given transport. I.e., does the sending and receiving of PDUs to remote home servers. The layer communicates with the rest of the server via a registered ReplicationHandler. In more detail, the layer: * Receives incoming data and processes it into transactions and pdus. * Fetches any PDUs it thinks it might have missed. * Keeps the current state for contexts up to date by applying the suitable conflict resolution. * Sends outgoing pdus wrapped in transactions. * Fills out the references to previous pdus/transactions appropriately for outgoing data. """ def __init__(self, hs, transport_layer): self.server_name = hs.hostname self.transport_layer = transport_layer self.transport_layer.register_received_handler(self) self.transport_layer.register_request_handler(self) self.store = hs.get_datastore() # self.pdu_actions = PduActions(self.store) self.transaction_actions = TransactionActions(self.store) self._transaction_queue = _TransactionQueue( hs, self.transaction_actions, transport_layer ) self.handler = None self.edu_handlers = {} self.query_handlers = {} self._order = 0 self._clock = hs.get_clock() self.event_builder_factory = hs.get_event_builder_factory() def set_handler(self, handler): """Sets the handler that the replication layer will use to communicate receipt of new PDUs from other home servers. The required methods are documented on :py:class:`.ReplicationHandler`. """ self.handler = handler def register_edu_handler(self, edu_type, handler): if edu_type in self.edu_handlers: raise KeyError("Already have an EDU handler for %s" % (edu_type,)) self.edu_handlers[edu_type] = handler def register_query_handler(self, query_type, handler): """Sets the handler callable that will be used to handle an incoming federation Query of the given type. Args: query_type (str): Category name of the query, which should match the string used by make_query. handler (callable): Invoked to handle incoming queries of this type handler is invoked as: result = handler(args) where 'args' is a dict mapping strings to strings of the query arguments. It should return a Deferred that will eventually yield an object to encode as JSON. """ if query_type in self.query_handlers: raise KeyError( "Already have a Query handler for %s" % (query_type,) ) self.query_handlers[query_type] = handler @log_function def send_pdu(self, pdu, destinations): """Informs the replication layer about a new PDU generated within the home server that should be transmitted to others. TODO: Figure out when we should actually resolve the deferred. Args: pdu (Pdu): The new Pdu. Returns: Deferred: Completes when we have successfully processed the PDU and replicated it to any interested remote home servers. """ order = self._order self._order += 1 logger.debug("[%s] transaction_layer.enqueue_pdu... ", pdu.event_id) # TODO, add errback, etc. self._transaction_queue.enqueue_pdu(pdu, destinations, order) logger.debug( "[%s] transaction_layer.enqueue_pdu... done", pdu.event_id ) @log_function def send_edu(self, destination, edu_type, content): edu = Edu( origin=self.server_name, destination=destination, edu_type=edu_type, content=content, ) # TODO, add errback, etc. self._transaction_queue.enqueue_edu(edu) return defer.succeed(None) @log_function def send_failure(self, failure, destination): self._transaction_queue.enqueue_failure(failure, destination) return defer.succeed(None) @log_function def make_query(self, destination, query_type, args, retry_on_dns_fail=True): """Sends a federation Query to a remote homeserver of the given type and arguments. Args: destination (str): Domain name of the remote homeserver query_type (str): Category of the query type; should match the handler name used in register_query_handler(). args (dict): Mapping of strings to strings containing the details of the query request. Returns: a Deferred which will eventually yield a JSON object from the response """ return self.transport_layer.make_query( destination, query_type, args, retry_on_dns_fail=retry_on_dns_fail ) @defer.inlineCallbacks @log_function def backfill(self, dest, context, limit, extremities): """Requests some more historic PDUs for the given context from the given destination server. Args: dest (str): The remote home server to ask. context (str): The context to backfill. limit (int): The maximum number of PDUs to return. extremities (list): List of PDU id and origins of the first pdus we have seen from the context Returns: Deferred: Results in the received PDUs. """ logger.debug("backfill extrem=%s", extremities) # If there are no extremeties then we've (probably) reached the start. if not extremities: return transaction_data = yield self.transport_layer.backfill( dest, context, extremities, limit) logger.debug("backfill transaction_data=%s", repr(transaction_data)) transaction = Transaction(**transaction_data) pdus = [ self.event_from_pdu_json(p, outlier=False) for p in transaction.pdus ] for pdu in pdus: yield self._handle_new_pdu(dest, pdu, backfilled=True) defer.returnValue(pdus) @defer.inlineCallbacks @log_function def get_pdu(self, destination, event_id, outlier=False): """Requests the PDU with given origin and ID from the remote home server. This will persist the PDU locally upon receipt. Args: destination (str): Which home server to query pdu_origin (str): The home server that originally sent the pdu. event_id (str) outlier (bool): Indicates whether the PDU is an `outlier`, i.e. if it's from an arbitary point in the context as opposed to part of the current block of PDUs. Defaults to `False` Returns: Deferred: Results in the requested PDU. """ transaction_data = yield self.transport_layer.get_event( destination, event_id ) transaction = Transaction(**transaction_data) pdu_list = [ self.event_from_pdu_json(p, outlier=outlier) for p in transaction.pdus ] pdu = None if pdu_list: pdu = pdu_list[0] yield self._handle_new_pdu(destination, pdu) defer.returnValue(pdu) @defer.inlineCallbacks @log_function def get_state_for_context(self, destination, context, event_id): """Requests all of the `current` state PDUs for a given context from a remote home server. Args: destination (str): The remote homeserver to query for the state. context (str): The context we're interested in. event_id (str): The id of the event we want the state at. Returns: Deferred: Results in a list of PDUs. """ result = yield self.transport_layer.get_context_state( destination, context, event_id=event_id, ) pdus = [ self.event_from_pdu_json(p, outlier=True) for p in result["pdus"] ] auth_chain = [ self.event_from_pdu_json(p, outlier=True) for p in result.get("auth_chain", []) ] defer.returnValue((pdus, auth_chain)) @defer.inlineCallbacks @log_function def get_event_auth(self, destination, context, event_id): res = yield self.transport_layer.get_event_auth( destination, context, event_id, ) auth_chain = [ self.event_from_pdu_json(p, outlier=True) for p in res["auth_chain"] ] auth_chain.sort(key=lambda e: e.depth) defer.returnValue(auth_chain) @defer.inlineCallbacks @log_function def on_backfill_request(self, origin, context, versions, limit): pdus = yield self.handler.on_backfill_request( origin, context, versions, limit ) defer.returnValue((200, self._transaction_from_pdus(pdus).get_dict())) @defer.inlineCallbacks @log_function def on_incoming_transaction(self, transaction_data): transaction = Transaction(**transaction_data) for p in transaction.pdus: if "unsigned" in p: unsigned = p["unsigned"] if "age" in unsigned: p["age"] = unsigned["age"] if "age" in p: p["age_ts"] = int(self._clock.time_msec()) - int(p["age"]) del p["age"] pdu_list = [ self.event_from_pdu_json(p) for p in transaction.pdus ] logger.debug("[%s] Got transaction", transaction.transaction_id) response = yield self.transaction_actions.have_responded(transaction) if response: logger.debug("[%s] We've already responed to this request", transaction.transaction_id) defer.returnValue(response) return logger.debug("[%s] Transaction is new", transaction.transaction_id) with PreserveLoggingContext(): dl = [] for pdu in pdu_list: dl.append(self._handle_new_pdu(transaction.origin, pdu)) if hasattr(transaction, "edus"): for edu in [Edu(**x) for x in transaction.edus]: self.received_edu( transaction.origin, edu.edu_type, edu.content ) results = yield defer.DeferredList(dl) ret = [] for r in results: if r[0]: ret.append({}) else: logger.exception(r[1]) ret.append({"error": str(r[1])}) logger.debug("Returning: %s", str(ret)) yield self.transaction_actions.set_response( transaction, 200, response ) defer.returnValue((200, response)) def received_edu(self, origin, edu_type, content): if edu_type in self.edu_handlers: self.edu_handlers[edu_type](origin, content) else: logger.warn("Received EDU of type %s with no handler", edu_type) @defer.inlineCallbacks @log_function def on_context_state_request(self, origin, context, event_id): if event_id: pdus = yield self.handler.get_state_for_pdu( origin, context, event_id, ) auth_chain = yield self.store.get_auth_chain( [pdu.event_id for pdu in pdus] ) else: raise NotImplementedError("Specify an event") defer.returnValue((200, { "pdus": [pdu.get_pdu_json() for pdu in pdus], "auth_chain": [pdu.get_pdu_json() for pdu in auth_chain], })) @defer.inlineCallbacks @log_function def on_pdu_request(self, origin, event_id): pdu = yield self._get_persisted_pdu(origin, event_id) if pdu: defer.returnValue( (200, self._transaction_from_pdus([pdu]).get_dict()) ) else: defer.returnValue((404, "")) @defer.inlineCallbacks @log_function def on_pull_request(self, origin, versions): raise NotImplementedError("Pull transacions not implemented") @defer.inlineCallbacks def on_query_request(self, query_type, args): if query_type in self.query_handlers: response = yield self.query_handlers[query_type](args) defer.returnValue((200, response)) else: defer.returnValue( (404, "No handler for Query type '%s'" % (query_type, )) ) @defer.inlineCallbacks def on_make_join_request(self, context, user_id): pdu = yield self.handler.on_make_join_request(context, user_id) time_now = self._clock.time_msec() defer.returnValue({ "event": pdu.get_pdu_json(time_now), }) @defer.inlineCallbacks def on_invite_request(self, origin, content): pdu = self.event_from_pdu_json(content) ret_pdu = yield self.handler.on_invite_request(origin, pdu) time_now = self._clock.time_msec() defer.returnValue( ( 200, { "event": ret_pdu.get_pdu_json(time_now), } ) ) @defer.inlineCallbacks def on_send_join_request(self, origin, content): logger.debug("on_send_join_request: content: %s", content) pdu = self.event_from_pdu_json(content) logger.debug("on_send_join_request: pdu sigs: %s", pdu.signatures) res_pdus = yield self.handler.on_send_join_request(origin, pdu) time_now = self._clock.time_msec() defer.returnValue((200, { "state": [p.get_pdu_json(time_now) for p in res_pdus["state"]], "auth_chain": [ p.get_pdu_json(time_now) for p in res_pdus["auth_chain"] ], })) @defer.inlineCallbacks def on_event_auth(self, origin, context, event_id): time_now = self._clock.time_msec() auth_pdus = yield self.handler.on_event_auth(event_id) defer.returnValue( ( 200, { "auth_chain": [ a.get_pdu_json(time_now) for a in auth_pdus ], } ) ) @defer.inlineCallbacks def make_join(self, destination, context, user_id): ret = yield self.transport_layer.make_join( destination=destination, context=context, user_id=user_id, ) pdu_dict = ret["event"] logger.debug("Got response to make_join: %s", pdu_dict) defer.returnValue(self.event_from_pdu_json(pdu_dict)) @defer.inlineCallbacks def send_join(self, destination, pdu): time_now = self._clock.time_msec() _, content = yield self.transport_layer.send_join( destination, pdu.room_id, pdu.event_id, pdu.get_pdu_json(time_now), ) logger.debug("Got content: %s", content) state = [ self.event_from_pdu_json(p, outlier=True) for p in content.get("state", []) ] # FIXME: We probably want to do something with the auth_chain given # to us auth_chain = [ self.event_from_pdu_json(p, outlier=True) for p in content.get("auth_chain", []) ] auth_chain.sort(key=lambda e: e.depth) defer.returnValue({ "state": state, "auth_chain": auth_chain, }) @defer.inlineCallbacks def send_invite(self, destination, context, event_id, pdu): time_now = self._clock.time_msec() code, content = yield self.transport_layer.send_invite( destination=destination, context=context, event_id=event_id, content=pdu.get_pdu_json(time_now), ) pdu_dict = content["event"] logger.debug("Got response to send_invite: %s", pdu_dict) defer.returnValue(self.event_from_pdu_json(pdu_dict)) @log_function def _get_persisted_pdu(self, origin, event_id, do_auth=True): """ Get a PDU from the database with given origin and id. Returns: Deferred: Results in a `Pdu`. """ return self.handler.get_persisted_pdu( origin, event_id, do_auth=do_auth ) def _transaction_from_pdus(self, pdu_list): """Returns a new Transaction containing the given PDUs suitable for transmission. """ time_now = self._clock.time_msec() pdus = [p.get_pdu_json(time_now) for p in pdu_list] return Transaction( origin=self.server_name, pdus=pdus, origin_server_ts=int(time_now), destination=None, ) @defer.inlineCallbacks @log_function def _handle_new_pdu(self, origin, pdu, backfilled=False): # We reprocess pdus when we have seen them only as outliers existing = yield self._get_persisted_pdu( origin, pdu.event_id, do_auth=False ) already_seen = ( existing and ( not existing.internal_metadata.is_outlier() or pdu.internal_metadata.is_outlier() ) ) if already_seen: logger.debug("Already seen pdu %s", pdu.event_id) defer.returnValue({}) return state = None auth_chain = [] # We need to make sure we have all the auth events. # for e_id, _ in pdu.auth_events: # exists = yield self._get_persisted_pdu( # origin, # e_id, # do_auth=False # ) # # if not exists: # try: # logger.debug( # "_handle_new_pdu fetch missing auth event %s from %s", # e_id, # origin, # ) # # yield self.get_pdu( # origin, # event_id=e_id, # outlier=True, # ) # # logger.debug("Processed pdu %s", e_id) # except: # logger.warn( # "Failed to get auth event %s from %s", # e_id, # origin # ) # Get missing pdus if necessary. if not pdu.internal_metadata.is_outlier(): # We only backfill backwards to the min depth. min_depth = yield self.handler.get_min_depth_for_context( pdu.room_id ) logger.debug( "_handle_new_pdu min_depth for %s: %d", pdu.room_id, min_depth ) if min_depth and pdu.depth > min_depth: for event_id, hashes in pdu.prev_events: exists = yield self._get_persisted_pdu( origin, event_id, do_auth=False ) if not exists: logger.debug( "_handle_new_pdu requesting pdu %s", event_id ) try: yield self.get_pdu( origin, event_id=event_id, ) logger.debug("Processed pdu %s", event_id) except: # TODO(erikj): Do some more intelligent retries. logger.exception("Failed to get PDU") else: # We need to get the state at this event, since we have reached # a backward extremity edge. logger.debug( "_handle_new_pdu getting state for %s", pdu.room_id ) state, auth_chain = yield self.get_state_for_context( origin, pdu.room_id, pdu.event_id, ) if not backfilled: ret = yield self.handler.on_receive_pdu( origin, pdu, backfilled=backfilled, state=state, auth_chain=auth_chain, ) else: ret = None # yield self.pdu_actions.mark_as_processed(pdu) defer.returnValue(ret) def __str__(self): return "<ReplicationLayer(%s)>" % self.server_name def event_from_pdu_json(self, pdu_json, outlier=False): event = FrozenEvent( pdu_json ) event.internal_metadata.outlier = outlier return event class _TransactionQueue(object): """This class makes sure we only have one transaction in flight at a time for a given destination. It batches pending PDUs into single transactions. """ def __init__(self, hs, transaction_actions, transport_layer): self.server_name = hs.hostname self.transaction_actions = transaction_actions self.transport_layer = transport_layer self._clock = hs.get_clock() self.store = hs.get_datastore() # Is a mapping from destinations -> deferreds. Used to keep track # of which destinations have transactions in flight and when they are # done self.pending_transactions = {} # Is a mapping from destination -> list of # tuple(pending pdus, deferred, order) self.pending_pdus_by_dest = {} # destination -> list of tuple(edu, deferred) self.pending_edus_by_dest = {} # destination -> list of tuple(failure, deferred) self.pending_failures_by_dest = {} # HACK to get unique tx id self._next_txn_id = int(self._clock.time_msec()) @defer.inlineCallbacks @log_function def enqueue_pdu(self, pdu, destinations, order): # We loop through all destinations to see whether we already have # a transaction in progress. If we do, stick it in the pending_pdus # table and we'll get back to it later. destinations = set(destinations) destinations.discard(self.server_name) logger.debug("Sending to: %s", str(destinations)) if not destinations: return deferreds = [] for destination in destinations: deferred = defer.Deferred() self.pending_pdus_by_dest.setdefault(destination, []).append( (pdu, deferred, order) ) def eb(failure): if not deferred.called: deferred.errback(failure) else: logger.warn("Failed to send pdu", failure) with PreserveLoggingContext(): self._attempt_new_transaction(destination).addErrback(eb) deferreds.append(deferred) yield defer.DeferredList(deferreds) # NO inlineCallbacks def enqueue_edu(self, edu): destination = edu.destination if destination == self.server_name: return deferred = defer.Deferred() self.pending_edus_by_dest.setdefault(destination, []).append( (edu, deferred) ) def eb(failure): if not deferred.called: deferred.errback(failure) else: logger.warn("Failed to send edu", failure) with PreserveLoggingContext(): self._attempt_new_transaction(destination).addErrback(eb) return deferred @defer.inlineCallbacks def enqueue_failure(self, failure, destination): deferred = defer.Deferred() self.pending_failures_by_dest.setdefault( destination, [] ).append( (failure, deferred) ) yield deferred @defer.inlineCallbacks @log_function def _attempt_new_transaction(self, destination): (retry_last_ts, retry_interval) = (0, 0) retry_timings = yield self.store.get_destination_retry_timings( destination ) if retry_timings: (retry_last_ts, retry_interval) = ( retry_timings.retry_last_ts, retry_timings.retry_interval ) if retry_last_ts + retry_interval > int(self._clock.time_msec()): logger.info( "TX [%s] not ready for retry yet - " "dropping transaction for now", destination, ) return else: logger.info("TX [%s] is ready for retry", destination) if destination in self.pending_transactions: # XXX: pending_transactions can get stuck on by a never-ending # request at which point pending_pdus_by_dest just keeps growing. # we need application-layer timeouts of some flavour of these # requests return # list of (pending_pdu, deferred, order) pending_pdus = self.pending_pdus_by_dest.pop(destination, []) pending_edus = self.pending_edus_by_dest.pop(destination, []) pending_failures = self.pending_failures_by_dest.pop(destination, []) if not pending_pdus and not pending_edus and not pending_failures: return logger.debug( "TX [%s] Attempting new transaction " "(pdus: %d, edus: %d, failures: %d)", destination, len(pending_pdus), len(pending_edus), len(pending_failures) ) # Sort based on the order field pending_pdus.sort(key=lambda t: t[2]) pdus = [x[0] for x in pending_pdus] edus = [x[0] for x in pending_edus] failures = [x[0].get_dict() for x in pending_failures] deferreds = [ x[1] for x in pending_pdus + pending_edus + pending_failures ] try: self.pending_transactions[destination] = 1 logger.debug("TX [%s] Persisting transaction...", destination) transaction = Transaction.create_new( origin_server_ts=int(self._clock.time_msec()), transaction_id=str(self._next_txn_id), origin=self.server_name, destination=destination, pdus=pdus, edus=edus, pdu_failures=failures, ) self._next_txn_id += 1 yield self.transaction_actions.prepare_to_send(transaction) logger.debug("TX [%s] Persisted transaction", destination) logger.info( "TX [%s] Sending transaction [%s]", destination, transaction.transaction_id, ) # Actually send the transaction # FIXME (erikj): This is a bit of a hack to make the Pdu age # keys work def json_data_cb(): data = transaction.get_dict() now = int(self._clock.time_msec()) if "pdus" in data: for p in data["pdus"]: if "age_ts" in p: unsigned = p.setdefault("unsigned", {}) unsigned["age"] = now - int(p["age_ts"]) del p["age_ts"] return data code, response = yield self.transport_layer.send_transaction( transaction, json_data_cb ) logger.info("TX [%s] got %d response", destination, code) logger.debug("TX [%s] Sent transaction", destination) logger.debug("TX [%s] Marking as delivered...", destination) yield self.transaction_actions.delivered( transaction, code, response ) logger.debug("TX [%s] Marked as delivered", destination) logger.debug("TX [%s] Yielding to callbacks...", destination) for deferred in deferreds: if code == 200: if retry_last_ts: # this host is alive! reset retry schedule yield self.store.set_destination_retry_timings( destination, 0, 0 ) deferred.callback(None) else: self.set_retrying(destination, retry_interval) deferred.errback(RuntimeError("Got status %d" % code)) # Ensures we don't continue until all callbacks on that # deferred have fired try: yield deferred except: pass logger.debug("TX [%s] Yielded to callbacks", destination) except Exception as e: # We capture this here as there as nothing actually listens # for this finishing functions deferred. logger.warn( "TX [%s] Problem in _attempt_transaction: %s", destination, e, ) self.set_retrying(destination, retry_interval) for deferred in deferreds: if not deferred.called: deferred.errback(e) finally: # We want to be *very* sure we delete this after we stop processing self.pending_transactions.pop(destination, None) # Check to see if there is anything else to send. self._attempt_new_transaction(destination) @defer.inlineCallbacks def set_retrying(self, destination, retry_interval): # track that this destination is having problems and we should # give it a chance to recover before trying it again if retry_interval: retry_interval *= 2 # plateau at hourly retries for now if retry_interval >= 60 * 60 * 1000: retry_interval = 60 * 60 * 1000 else: retry_interval = 2000 # try again at first after 2 seconds yield self.store.set_destination_retry_timings( destination, int(self._clock.time_msec()), retry_interval )