Merge pull request #42 from matrix-org/replication_split

Replication split

1 files changed, 345 insertions, 0 deletions

diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
new file mode 100644
index 0000000000..0597725ce7
--- /dev/null
+++ b/synapse/federation/federation_server.py
@@ -0,0 +1,345 @@
+# -*- coding: utf-8 -*-
+# Copyright 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.
+
+
+from twisted.internet import defer
+
+from .units import Transaction, Edu
+
+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 FederationServer(object):
+    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
+
+    @defer.inlineCallbacks
+    @log_function
+    def on_backfill_request(self, origin, room_id, versions, limit):
+        pdus = yield self.handler.on_backfill_request(
+            origin, room_id, 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, room_id, event_id):
+        if event_id:
+            pdus = yield self.handler.get_state_for_pdu(
+                origin, room_id, 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 transactions 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, room_id, user_id):
+        pdu = yield self.handler.on_make_join_request(room_id, 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, room_id, 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],
+        }))
+
+    @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, max_recursion=10):
+        # 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 = []
+
+        have_seen = yield self.store.have_events(
+            [e for e, _ in pdu.prev_events]
+        )
+
+        # 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 and max_recursion > 0:
+                for event_id, hashes in pdu.prev_events:
+                    if event_id not in have_seen:
+                        logger.debug(
+                            "_handle_new_pdu requesting pdu %s",
+                            event_id
+                        )
+
+                        try:
+                            new_pdu = yield self.federation_client.get_pdu(
+                                [origin, pdu.origin],
+                                event_id=event_id,
+                            )
+
+                            if new_pdu:
+                                yield self._handle_new_pdu(
+                                    origin,
+                                    new_pdu,
+                                    max_recursion=max_recursion-1
+                                )
+
+                                logger.debug("Processed pdu %s", event_id)
+                            else:
+                                logger.warn("Failed to get 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_room(
+                    origin, pdu.room_id, pdu.event_id,
+                )
+
+        ret = yield self.handler.on_receive_pdu(
+            origin,
+            pdu,
+            backfilled=False,
+            state=state,
+            auth_chain=auth_chain,
+        )
+
+        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