From 314b146b2e3082fc6bc61296f5c2ea5d7735f01e Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 29 Jun 2016 11:41:20 +0100
Subject: [PATCH] Track approximate last access time for remote media

---
 synapse/rest/media/v1/media_repository.py     | 24 ++++++++++++++
 synapse/storage/media_repository.py           | 15 +++++++++
 synapse/storage/prepare_database.py           |  2 +-
 .../schema/delta/33/remote_media_ts.py        | 31 +++++++++++++++++++
 4 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 synapse/storage/schema/delta/33/remote_media_ts.py

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 2468c3ac4..1a287b6fe 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -43,6 +43,9 @@ import urlparse
 logger = logging.getLogger(__name__)
 
 
+UPDATE_RECENTLY_ACCESSED_REMOTES_TS = 60 * 1000
+
+
 class MediaRepository(object):
     def __init__(self, hs, filepaths):
         self.auth = hs.get_auth()
@@ -57,6 +60,22 @@ class MediaRepository(object):
         self.dynamic_thumbnails = hs.config.dynamic_thumbnails
         self.thumbnail_requirements = hs.config.thumbnail_requirements
 
+        self.recently_accessed_remotes = set()
+
+        self.clock.looping_call(
+            self._update_recently_accessed_remotes,
+            UPDATE_RECENTLY_ACCESSED_REMOTES_TS
+        )
+
+    @defer.inlineCallbacks
+    def _update_recently_accessed_remotes(self):
+        media = self.recently_accessed_remotes
+        self.recently_accessed_remotes = set()
+
+        yield self.store.update_cached_last_access_time(
+            media, self.clock.time_msec()
+        )
+
     @staticmethod
     def _makedirs(filepath):
         dirname = os.path.dirname(filepath)
@@ -119,6 +138,11 @@ class MediaRepository(object):
             media_info = yield self._download_remote_file(
                 server_name, media_id
             )
+        else:
+            self.recently_accessed_remotes.add((server_name, media_id))
+            yield self.store.update_cached_last_access_time(
+                [(server_name, media_id)], self.clock.time_msec()
+            )
         defer.returnValue(media_info)
 
     @defer.inlineCallbacks
diff --git a/synapse/storage/media_repository.py b/synapse/storage/media_repository.py
index a820fcf07..44e4d3830 100644
--- a/synapse/storage/media_repository.py
+++ b/synapse/storage/media_repository.py
@@ -157,10 +157,25 @@ class MediaRepositoryStore(SQLBaseStore):
                 "created_ts": time_now_ms,
                 "upload_name": upload_name,
                 "filesystem_id": filesystem_id,
+                "last_access_ts": time_now_ms,
             },
             desc="store_cached_remote_media",
         )
 
+    def update_cached_last_access_time(self, origin_id_tuples, time_ts):
+        def update_cache_txn(txn):
+            sql = (
+                "UPDATE remote_media_cache SET last_access_ts = ?"
+                " WHERE media_origin = ? AND media_id = ?"
+            )
+
+            txn.executemany(sql, (
+                (time_ts, media_origin, media_id)
+                for media_origin, media_id in origin_id_tuples
+            ))
+
+        return self.runInteraction("update_cached_last_access_time", update_cache_txn)
+
     def get_remote_media_thumbnails(self, origin, media_id):
         return self._simple_select_list(
             "remote_media_cache_thumbnails",
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index c8487c883..8801669a6 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -25,7 +25,7 @@ logger = logging.getLogger(__name__)
 
 # 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 = 32
+SCHEMA_VERSION = 33
 
 dir_path = os.path.abspath(os.path.dirname(__file__))
 
diff --git a/synapse/storage/schema/delta/33/remote_media_ts.py b/synapse/storage/schema/delta/33/remote_media_ts.py
new file mode 100644
index 000000000..55ae43f39
--- /dev/null
+++ b/synapse/storage/schema/delta/33/remote_media_ts.py
@@ -0,0 +1,31 @@
+# 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.
+
+import time
+
+
+ALTER_TABLE = "ALTER TABLE remote_media_cache ADD COLUMN last_access_ts BIGINT"
+
+
+def run_create(cur, database_engine, *args, **kwargs):
+    cur.execute(ALTER_TABLE)
+
+
+def run_upgrade(cur, database_engine, *args, **kwargs):
+    cur.execute(
+        database_engine.convert_param_style(
+            "UPDATE remote_media_cache SET last_access_ts = ?"
+        ),
+        (int(time.time() * 1000),)
+    )