Implement tracking event format versions

synapse/api/constants.py

@@ -119,6 +119,19 @@ class RoomVersions(object):
     RoomVersions.STATE_V2_TEST,
 }
 
+
+class EventFormatVersions(object):
+    """This is an internal enum for tracking the version of the event format,
+    independently from the room version.
+    """
+    V1 = 1
+
+
+KNOWN_EVENT_FORMAT_VERSIONS = {
+    EventFormatVersions.V1,
+}
+
+
 ServerNoticeMsgType = "m.server_notice"
 ServerNoticeLimitReached = "m.server_notice.usage_limit_reached"
 

synapse/events/__init__.py

@@ -18,7 +18,11 @@
 
 import six
 
-from synapse.api.constants import KNOWN_ROOM_VERSIONS
+from synapse.api.constants import (
+    KNOWN_EVENT_FORMAT_VERSIONS,
+    KNOWN_ROOM_VERSIONS,
+    EventFormatVersions,
+)
 from synapse.util.caches import intern_dict
 from synapse.util.frozenutils import freeze
 
@@ -180,6 +184,8 @@ def auth_event_ids(self):
 
 
 class FrozenEvent(EventBase):
+    format_version = EventFormatVersions.V1  # All events of this type are V1
+
     def __init__(self, event_dict, internal_metadata_dict={}, rejected_reason=None):
         event_dict = dict(event_dict)
 
@@ -244,3 +250,14 @@ def event_type_from_room_version(room_version):
             "No event format defined for version %r" % (room_version,)
         )
     return FrozenEvent
+
+
+def event_type_from_format_version(format_version):
+    """Returns the python type to use to construct an Event object for the
+    given event format version.
+    """
+    if format_version not in KNOWN_EVENT_FORMAT_VERSIONS:
+        raise Exception(
+            "No event format %r" % (format_version,)
+        )
+    return FrozenEvent

synapse/storage/events.py

@@ -1256,6 +1256,7 @@ def event_dict(event):
                         event.internal_metadata.get_dict()
                     ),
                     "json": encode_json(event_dict(event)),
+                    "format_version": event.format_version,
                 }
                 for event, _ in events_and_contexts
             ],

synapse/storage/events_worker.py

@@ -21,8 +21,9 @@
 
 from twisted.internet import defer
 
+from synapse.api.constants import EventFormatVersions
 from synapse.api.errors import NotFoundError
-from synapse.events import event_type_from_room_version
+from synapse.events import event_type_from_format_version
 # these are only included to make the type annotations work
 from synapse.events.snapshot import EventContext  # noqa: F401
 from synapse.events.utils import prune_event
@@ -352,6 +353,7 @@ def _enqueue_events(self, events, check_redacted=True, allow_rejected=False):
                     self._get_event_from_row,
                     row["internal_metadata"], row["json"], row["redacts"],
                     rejected_reason=row["rejects"],
+                    format_version=row["format_version"],
                 )
                 for row in rows
             ],
@@ -376,6 +378,7 @@ def _fetch_event_rows(self, txn, events):
                 " e.event_id as event_id, "
                 " e.internal_metadata,"
                 " e.json,"
+                " e.format_version, "
                 " r.redacts as redacts,"
                 " rej.event_id as rejects "
                 " FROM event_json as e"
@@ -391,7 +394,7 @@ def _fetch_event_rows(self, txn, events):
 
     @defer.inlineCallbacks
     def _get_event_from_row(self, internal_metadata, js, redacted,
-                            rejected_reason=None):
+                            format_version, rejected_reason=None):
         with Measure(self._clock, "_get_event_from_row"):
             d = json.loads(js)
             internal_metadata = json.loads(internal_metadata)
@@ -404,7 +407,12 @@ def _get_event_from_row(self, internal_metadata, js, redacted,
                     desc="_get_event_from_row_rejected_reason",
                 )
 
-            original_ev = event_type_from_room_version("1")(  # FIXME
+            if format_version is None:
+                # This means that we stored the event before we had the concept
+                # of a event format version, so it must be a V1 event.
+                format_version = EventFormatVersions.V1
+
+            original_ev = event_type_from_format_version(format_version)(
                 event_dict=d,
                 internal_metadata_dict=internal_metadata,
                 rejected_reason=rejected_reason,

synapse/storage/prepare_database.py

@@ -25,7 +25,7 @@
 
 # Remember to update this number every time a change is made to database
 # schema files, so the users will be informed on server restarts.
-SCHEMA_VERSION = 53
+SCHEMA_VERSION = 54
 
 dir_path = os.path.abspath(os.path.dirname(__file__))
 

synapse/storage/schema/delta/54/event_format_version.sql

@@ -0,0 +1,16 @@
+/* Copyright 2019 New Vector 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.
+ */
+
+ALTER TABLE event_json ADD COLUMN format_version INTEGER;