Add a slaved receipts store

synapse/replication/slave/storage/receipts.py

@@ -0,0 +1,61 @@
+# -*- coding: utf-8 -*-
+# Copyright 2016 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 ._base import BaseSlavedStore
+from ._slaved_id_tracker import SlavedIdTracker
+
+from synapse.storage import DataStore
+from synapse.storage.receipts import ReceiptsStore
+
+# So, um, we want to borrow a load of functions intended for reading from
+# a DataStore, but we don't want to take functions that either write to the
+# DataStore or are cached and don't have cache invalidation logic.
+#
+# Rather than write duplicate versions of those functions, or lift them to
+# a common base class, we going to grab the underlying __func__ object from
+# the method descriptor on the DataStore and chuck them into our class.
+
+
+class SlavedReceiptsStore(BaseSlavedStore):
+
+    def __init__(self, db_conn, hs):
+        super(SlavedReceiptsStore, self).__init__(db_conn, hs)
+
+        self._receipts_id_gen = SlavedIdTracker(
+            db_conn, "receipts_linearized", "stream_id"
+        )
+
+    get_receipts_for_user = ReceiptsStore.__dict__["get_receipts_for_user"]
+
+    get_max_receipt_stream_id = DataStore.get_max_receipt_stream_id.__func__
+    get_all_updated_receipts = DataStore.get_all_updated_receipts.__func__
+
+    def stream_positions(self):
+        result = super(SlavedReceiptsStore, self).stream_positions()
+        result["receipts"] = self._receipts_id_gen.get_current_token()
+        return result
+
+    def process_replication(self, result):
+        stream = result.get("receipts")
+        if stream:
+            self._receipts_id_gen.advance(stream["position"])
+            for row in stream["rows"]:
+                room_id, receipt_type, user_id = row[1:4]
+                self.invalidate_caches_for_receipt(room_id, receipt_type, user_id)
+
+        return super(SlavedReceiptsStore, self).process_replication(result)
+
+    def invalidate_caches_for_receipt(self, room_id, receipt_type, user_id):
+        self.get_receipts_for_user.invalidate((user_id, receipt_type))