Add automatic purge after all users forgotten a room

changelog.d/15488.feature

@@ -0,0 +1 @@
+Add automatic purge after all users forgotten a room.

synapse/handlers/pagination.py

@@ -160,6 +160,7 @@ def __init__(self, hs: "HomeServer"):
         self._retention_allowed_lifetime_max = (
             hs.config.retention.retention_allowed_lifetime_max
         )
+        self._redaction_retention_period = hs.config.server.redaction_retention_period
         self._is_master = hs.config.worker.worker_app is None
 
         if hs.config.retention.retention_enabled and self._is_master:
@@ -176,6 +177,44 @@ def __init__(self, hs: "HomeServer"):
                     job.longest_max_lifetime,
                 )
 
+        if self._is_master:
+            self.clock.looping_call(
+                run_as_background_process,
+                3600 * 1000,
+                "purge_rooms",
+                self.purge_rooms,
+            )
+
+    async def purge_rooms(self) -> None:
+        rooms_to_purge = await self.store.get_rooms_to_purge()
+        for r in rooms_to_purge:
+            if r["status"] == "complete":
+                # TODO cleanup the table
+                continue
+
+            room_id = r["room_id"]
+            delete_id = r["delete_id"]
+
+            delete_status = self._delete_by_id.get(delete_id)
+            if delete_status is not None:
+                # a purge background task is already running (or has run)
+                # for this delete id
+                continue
+
+            purge_now = False
+            if r["timestamp"] is None:
+                purge_now = True
+            else:
+                time_since_marked = self.clock.time_msec() - r["timestamp"]
+                if time_since_marked >= self._redaction_retention_period:
+                    purge_now = True
+
+            # TODO 2 stages purge, keep memberships for a while so we don't "break" sync
+            if purge_now:
+                self._delete_by_id[delete_id] = DeleteStatus()
+                self._delete_by_room.setdefault(room_id, []).append(delete_id)
+                await self.purge_room(room_id, delete_id, True)
+
     async def purge_history_for_rooms_in_range(
         self, min_ms: Optional[int], max_ms: Optional[int]
     ) -> None:
@@ -399,22 +438,30 @@ def get_delete_ids_by_room(self, room_id: str) -> Optional[StrCollection]:
         """
         return self._delete_by_room.get(room_id)
 
-    async def purge_room(self, room_id: str, force: bool = False) -> None:
+    async def purge_room(
+        self,
+        room_id: str,
+        delete_id: str,
+        force: bool = False,
+    ) -> None:
         """Purge the given room from the database.
-        This function is part the delete room v1 API.
 
         Args:
             room_id: room to be purged
             force: set true to skip checking for joined users.
         """
+        logger.info("starting purge room_id %s", room_id)
+
         async with self.pagination_lock.write(room_id):
             # first check that we have no users in this room
             if not force:
                 joined = await self.store.is_host_joined(room_id, self._server_name)
                 if joined:
                     raise SynapseError(400, "Users are still joined to this room")
 
-            await self._storage_controllers.purge_events.purge_room(room_id)
+            await self._storage_controllers.purge_events.purge_room(room_id, delete_id)
+
+        logger.info("purge complete for room_id %s", room_id)
 
     @trace
     async def get_messages(
@@ -654,36 +701,22 @@ async def _shutdown_and_purge_room(
 
         self._purges_in_progress_by_room.add(room_id)
         try:
-            async with self.pagination_lock.write(room_id):
-                self._delete_by_id[delete_id].status = DeleteStatus.STATUS_SHUTTING_DOWN
-                self._delete_by_id[
-                    delete_id
-                ].shutdown_room = await self._room_shutdown_handler.shutdown_room(
-                    room_id=room_id,
-                    requester_user_id=requester_user_id,
-                    new_room_user_id=new_room_user_id,
-                    new_room_name=new_room_name,
-                    message=message,
-                    block=block,
-                )
-                self._delete_by_id[delete_id].status = DeleteStatus.STATUS_PURGING
-
-                if purge:
-                    logger.info("starting purge room_id %s", room_id)
-
-                    # first check that we have no users in this room
-                    if not force_purge:
-                        joined = await self.store.is_host_joined(
-                            room_id, self._server_name
-                        )
-                        if joined:
-                            raise SynapseError(
-                                400, "Users are still joined to this room"
-                            )
+            self._delete_by_id[delete_id].status = DeleteStatus.STATUS_SHUTTING_DOWN
+            self._delete_by_id[
+                delete_id
+            ].shutdown_room = await self._room_shutdown_handler.shutdown_room(
+                room_id=room_id,
+                requester_user_id=requester_user_id,
+                new_room_user_id=new_room_user_id,
+                new_room_name=new_room_name,
+                message=message,
+                block=block,
+            )
 
-                    await self._storage_controllers.purge_events.purge_room(room_id)
+            if purge:
+                self._delete_by_id[delete_id].status = DeleteStatus.STATUS_PURGING
+                await self.purge_room(room_id, delete_id, force_purge)
 
-            logger.info("purge complete for room_id %s", room_id)
             self._delete_by_id[delete_id].status = DeleteStatus.STATUS_COMPLETE
         except Exception:
             f = Failure()

synapse/handlers/room_member.py

@@ -2066,6 +2066,9 @@ async def forget(self, user: UserID, room_id: str) -> None:
         # the table `current_state_events` and `get_current_state_events` is `None`.
         await self.store.forget(user_id, room_id)
 
+        if await self.store.is_locally_forgotten_room(room_id):
+            await self.store.upsert_room_to_purge(room_id, None, self.clock.time_msec())
+
 
 def get_users_which_can_issue_invite(auth_events: StateMap[EventBase]) -> List[str]:
     """

synapse/rest/admin/rooms.py

@@ -39,6 +39,7 @@
 from synapse.types import JsonDict, RoomID, UserID, create_requester
 from synapse.types.state import StateFilter
 from synapse.util import json_decoder
+from synapse.util.stringutils import random_string
 
 if TYPE_CHECKING:
     from synapse.api.auth import Auth
@@ -356,10 +357,14 @@ async def _delete_room(
             block=block,
         )
 
+        delete_id = random_string(16)
+
         # Purge room
         if purge:
             try:
-                await pagination_handler.purge_room(room_id, force=force_purge)
+                await pagination_handler.purge_room(
+                    room_id, delete_id, force=force_purge
+                )
             except NotFoundError:
                 if block:
                     # We can block unknown rooms with this endpoint, in which case

synapse/rest/client/room.py

@@ -944,8 +944,10 @@ async def on_GET(
 class RoomForgetRestServlet(TransactionRestServlet):
     def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
+        self.store = hs.get_datastores().main
         self.room_member_handler = hs.get_room_member_handler()
         self.auth = hs.get_auth()
+        self.clock = hs.get_clock()
 
     def register(self, http_server: HttpServer) -> None:
         PATTERNS = "/rooms/(?P<room_id>[^/]*)/forget"

synapse/storage/controllers/purge_events.py

@@ -30,14 +30,23 @@ class PurgeEventsStorageController:
 
     def __init__(self, hs: "HomeServer", stores: Databases):
         self.stores = stores
+        self.clock = hs.get_clock()
 
-    async def purge_room(self, room_id: str) -> None:
+    async def purge_room(self, room_id: str, delete_id: str) -> None:
         """Deletes all record of a room"""
 
+        await self.stores.main.upsert_room_to_purge(
+            room_id, delete_id, self.clock.time_msec(), "purging"
+        )
+
         with nested_logging_context(room_id):
             state_groups_to_delete = await self.stores.main.purge_room(room_id)
             await self.stores.state.purge_room_state(room_id, state_groups_to_delete)
 
+        await self.stores.main.upsert_room_to_purge(
+            room_id, delete_id, self.clock.time_msec(), "complete"
+        )
+
     async def purge_history(
         self, room_id: str, token: str, delete_local_events: bool
     ) -> None:

synapse/storage/databases/main/roommember.py

@@ -17,6 +17,7 @@
 from typing import (
     TYPE_CHECKING,
     AbstractSet,
+    Any,
     Collection,
     Dict,
     FrozenSet,
@@ -1284,6 +1285,36 @@ async def is_locally_forgotten_room(self, room_id: str) -> bool:
         # If any rows still exist it means someone has not forgotten this room yet
         return not rows[0][0]
 
+    async def upsert_room_to_purge(
+        self,
+        room_id: str,
+        delete_id: Optional[str] = None,
+        timestamp: Optional[int] = None,
+        status: str = "waiting",
+    ) -> None:
+        await self.db_pool.simple_upsert(
+            "rooms_to_purge",
+            {
+                "room_id": room_id,
+                "delete_id": delete_id,
+            },
+            {
+                "room_id": room_id,
+                "delete_id": delete_id,
+                "timestamp": timestamp,
+                "status": status,
+            },
+            desc="upsert_room_to_purge",
+        )
+
+    async def get_rooms_to_purge(self) -> List[Dict[str, Any]]:
+        return await self.db_pool.simple_select_list(
+            table="rooms_to_purge",
+            keyvalues={},
+            retcols=("room_id", "delete_id", "timestamp", "status"),
+            desc="rooms_to_purge_fetch",
+        )
+
     async def get_rooms_user_has_been_in(self, user_id: str) -> Set[str]:
         """Get all rooms that the user has ever been in.
 

synapse/storage/schema/main/delta/76/03_rooms_to_purge.sql

@@ -0,0 +1,7 @@
+CREATE TABLE IF NOT EXISTS rooms_to_purge(
+    room_id text NOT NULL,
+    delete_id text,
+    "timestamp" bigint,
+    "status" text NOT NULL,
+    UNIQUE(room_id, delete_id)
+);

tests/rest/admin/test_room.py

@@ -27,6 +27,7 @@
 from synapse.handlers.pagination import PaginationHandler, PurgeStatus
 from synapse.rest.client import directory, events, login, room
 from synapse.server import HomeServer
+from synapse.types import UserID
 from synapse.util import Clock
 from synapse.util.stringutils import random_string
 
@@ -502,6 +503,9 @@ def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
         )
         self.url_status_by_delete_id = "/_synapse/admin/v2/rooms/delete_status/"
 
+        self.room_member_handler = hs.get_room_member_handler()
+        self.pagination_handler = hs.get_pagination_handler()
+
     @parameterized.expand(
         [
             ("DELETE", "/_synapse/admin/v2/rooms/%s"),
@@ -972,6 +976,25 @@ def test_shutdown_room_block_peek(self) -> None:
         # Assert we can no longer peek into the room
         self._assert_peek(self.room_id, expect_code=403)
 
+    @unittest.override_config({"redaction_retention_period": "0"})
+    def test_purge_forgotten_room(self) -> None:
+        # Create a test room
+        room_id = self.helper.create_room_as(
+            self.admin_user,
+            tok=self.admin_user_tok,
+        )
+
+        self.helper.leave(room_id, user=self.admin_user, tok=self.admin_user_tok)
+        self.get_success(
+            self.room_member_handler.forget(
+                UserID.from_string(self.admin_user), room_id
+            )
+        )
+
+        self.get_success(self.pagination_handler.purge_rooms())
+
+        self._is_purged(room_id)
+
     def _is_blocked(self, room_id: str, expect: bool = True) -> None:
         """Assert that the room is blocked or not"""
         d = self.store.is_room_blocked(room_id)

tests/rest/admin/test_server_notice.py

@@ -417,7 +417,7 @@ def test_send_server_notice_delete_room(self) -> None:
         self.get_success(
             self.room_shutdown_handler.shutdown_room(first_room_id, self.admin_user)
         )
-        self.get_success(self.pagination_handler.purge_room(first_room_id))
+        self.get_success(self.pagination_handler.purge_room(first_room_id, "delete_id"))
 
         # user is not member anymore
         self._check_invite_and_join_status(self.other_user, 0, 0)

tests/storage/test_purge.py

@@ -115,7 +115,7 @@ def test_purge_room(self) -> None:
 
         # Purge everything before this topological token
         self.get_success(
-            self._storage_controllers.purge_events.purge_room(self.room_id)
+            self._storage_controllers.purge_events.purge_room(self.room_id, "delete_id")
         )
 
         # The events aren't found.