Add config options for media retention (#12732)

tests/rest/media/test_media_retention.py

@@ -0,0 +1,238 @@
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# 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.
+
+import io
+from typing import Iterable, Optional, Tuple
+
+from twisted.test.proto_helpers import MemoryReactor
+
+from synapse.rest import admin
+from synapse.rest.client import login, register, room
+from synapse.server import HomeServer
+from synapse.types import UserID
+from synapse.util import Clock
+
+from tests import unittest
+from tests.unittest import override_config
+from tests.utils import MockClock
+
+
+class MediaRetentionTestCase(unittest.HomeserverTestCase):
+
+    ONE_DAY_IN_MS = 24 * 60 * 60 * 1000
+    THIRTY_DAYS_IN_MS = 30 * ONE_DAY_IN_MS
+
+    servlets = [
+        room.register_servlets,
+        login.register_servlets,
+        register.register_servlets,
+        admin.register_servlets_for_client_rest_resource,
+    ]
+
+    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
+        # We need to be able to test advancing time in the homeserver, so we
+        # replace the test homeserver's default clock with a MockClock, which
+        # supports advancing time.
+        return self.setup_test_homeserver(clock=MockClock())
+
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+        self.remote_server_name = "remote.homeserver"
+        self.store = hs.get_datastores().main
+
+        # Create a user to upload media with
+        test_user_id = self.register_user("alice", "password")
+
+        # Inject media (3 images each; recently accessed, old access, never accessed)
+        # into both the local store and the remote cache
+        media_repository = hs.get_media_repository()
+        test_media_content = b"example string"
+
+        def _create_media_and_set_last_accessed(
+            last_accessed_ms: Optional[int],
+        ) -> str:
+            # "Upload" some media to the local media store
+            mxc_uri = self.get_success(
+                media_repository.create_content(
+                    media_type="text/plain",
+                    upload_name=None,
+                    content=io.BytesIO(test_media_content),
+                    content_length=len(test_media_content),
+                    auth_user=UserID.from_string(test_user_id),
+                )
+            )
+
+            media_id = mxc_uri.split("/")[-1]
+
+            # Set the last recently accessed time for this media
+            if last_accessed_ms is not None:
+                self.get_success(
+                    self.store.update_cached_last_access_time(
+                        local_media=(media_id,),
+                        remote_media=(),
+                        time_ms=last_accessed_ms,
+                    )
+                )
+
+            return media_id
+
+        def _cache_remote_media_and_set_last_accessed(
+            media_id: str, last_accessed_ms: Optional[int]
+        ) -> str:
+            # Pretend to cache some remote media
+            self.get_success(
+                self.store.store_cached_remote_media(
+                    origin=self.remote_server_name,
+                    media_id=media_id,
+                    media_type="text/plain",
+                    media_length=1,
+                    time_now_ms=clock.time_msec(),
+                    upload_name="testfile.txt",
+                    filesystem_id="abcdefg12345",
+                )
+            )
+
+            # Set the last recently accessed time for this media
+            if last_accessed_ms is not None:
+                self.get_success(
+                    hs.get_datastores().main.update_cached_last_access_time(
+                        local_media=(),
+                        remote_media=((self.remote_server_name, media_id),),
+                        time_ms=last_accessed_ms,
+                    )
+                )
+
+            return media_id
+
+        # Start with the local media store
+        self.local_recently_accessed_media = _create_media_and_set_last_accessed(
+            self.THIRTY_DAYS_IN_MS
+        )
+        self.local_not_recently_accessed_media = _create_media_and_set_last_accessed(
+            self.ONE_DAY_IN_MS
+        )
+        self.local_never_accessed_media = _create_media_and_set_last_accessed(None)
+
+        # And now the remote media store
+        self.remote_recently_accessed_media = _cache_remote_media_and_set_last_accessed(
+            "a", self.THIRTY_DAYS_IN_MS
+        )
+        self.remote_not_recently_accessed_media = (
+            _cache_remote_media_and_set_last_accessed("b", self.ONE_DAY_IN_MS)
+        )
+        # Remote media will always have a "last accessed" attribute, as it would not
+        # be fetched from the remote homeserver unless instigated by a user.
+
+    @override_config(
+        {
+            "media_retention": {
+                # Enable retention for local media
+                "local_media_lifetime": "30d"
+                # Cached remote media should not be purged
+            }
+        }
+    )
+    def test_local_media_retention(self) -> None:
+        """
+        Tests that local media that have not been accessed recently is purged, while
+        cached remote media is unaffected.
+        """
+        # Advance 31 days (in seconds)
+        self.reactor.advance(31 * 24 * 60 * 60)
+
+        # Check that media has been correctly purged.
+        # Local media accessed <30 days ago should still exist.
+        # Remote media should be unaffected.
+        self._assert_if_mxc_uris_purged(
+            purged=[
+                (
+                    self.hs.config.server.server_name,
+                    self.local_not_recently_accessed_media,
+                ),
+                (self.hs.config.server.server_name, self.local_never_accessed_media),
+            ],
+            not_purged=[
+                (self.hs.config.server.server_name, self.local_recently_accessed_media),
+                (self.remote_server_name, self.remote_recently_accessed_media),
+                (self.remote_server_name, self.remote_not_recently_accessed_media),
+            ],
+        )
+
+    @override_config(
+        {
+            "media_retention": {
+                # Enable retention for cached remote media
+                "remote_media_lifetime": "30d"
+                # Local media should not be purged
+            }
+        }
+    )
+    def test_remote_media_cache_retention(self) -> None:
+        """
+        Tests that entries from the remote media cache that have not been accessed
+        recently is purged, while local media is unaffected.
+        """
+        # Advance 31 days (in seconds)
+        self.reactor.advance(31 * 24 * 60 * 60)
+
+        # Check that media has been correctly purged.
+        # Local media should be unaffected.
+        # Remote media accessed <30 days ago should still exist.
+        self._assert_if_mxc_uris_purged(
+            purged=[
+                (self.remote_server_name, self.remote_not_recently_accessed_media),
+            ],
+            not_purged=[
+                (self.remote_server_name, self.remote_recently_accessed_media),
+                (self.hs.config.server.server_name, self.local_recently_accessed_media),
+                (
+                    self.hs.config.server.server_name,
+                    self.local_not_recently_accessed_media,
+                ),
+                (self.hs.config.server.server_name, self.local_never_accessed_media),
+            ],
+        )
+
+    def _assert_if_mxc_uris_purged(
+        self, purged: Iterable[Tuple[str, str]], not_purged: Iterable[Tuple[str, str]]
+    ) -> None:
+        def _assert_mxc_uri_purge_state(
+            server_name: str, media_id: str, expect_purged: bool
+        ) -> None:
+            """Given an MXC URI, assert whether it has been purged or not."""
+            if server_name == self.hs.config.server.server_name:
+                found_media_dict = self.get_success(
+                    self.store.get_local_media(media_id)
+                )
+            else:
+                found_media_dict = self.get_success(
+                    self.store.get_cached_remote_media(server_name, media_id)
+                )
+
+            mxc_uri = f"mxc://{server_name}/{media_id}"
+
+            if expect_purged:
+                self.assertIsNone(
+                    found_media_dict, msg=f"{mxc_uri} unexpectedly not purged"
+                )
+            else:
+                self.assertIsNotNone(
+                    found_media_dict,
+                    msg=f"{mxc_uri} unexpectedly purged",
+                )
+
+        # Assert that the given MXC URIs have either been correctly purged or not.
+        for server_name, media_id in purged:
+            _assert_mxc_uri_purge_state(server_name, media_id, expect_purged=True)
+        for server_name, media_id in not_purged:
+            _assert_mxc_uri_purge_state(server_name, media_id, expect_purged=False)