From 531c4989dba50d6beb24443067d67f97caf1c042 Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Thu, 25 Jan 2024 11:41:55 +0000
Subject: [PATCH] cache: Remove avatars/images from cache if not used

This creates a simple LRU policy to evict items from the cache that have
not been accessed in 24 hours.

Fixes: #13547
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/backend/accounts.py | 18 ++++++++++++++----
 src/backend/wiki.py     | 19 ++++++++++++++++---
 src/web/users.py        | 17 +++++++++++++----
 3 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/src/backend/accounts.py b/src/backend/accounts.py
index 9df7d627..397f217c 100644
--- a/src/backend/accounts.py
+++ b/src/backend/accounts.py
@@ -1301,11 +1301,21 @@ class Account(LDAPObject):
 			return photo
 
 		# Compose the cache key
-		key = "accounts:%s:avatar:%s:%s:%s" \
+		cache_key = "accounts:%s:avatar:%s:%s:%s" \
 			% (self.uid, self.avatar_hash, format or "N/A", size)
 
-		# Try to retrieve something from the cache
-		avatar = await self.backend.cache.get(key)
+		# Try to fetch the data from the cache
+		async with await self.backend.cache.pipeline() as p:
+			# Fetch the key
+			await p.get(cache_key)
+
+			# Reset the TTL
+			await p.expire(cache_key, 86400)
+
+			# Execute the pipeline
+			avatar, _ = await p.execute()
+
+		# Return the cached value (if any)
 		if avatar:
 			return avatar
 
@@ -1313,7 +1323,7 @@ class Account(LDAPObject):
 		avatar = util.generate_thumbnail(photo, size, square=True, format=format)
 
 		# Save to cache for 24h
-		await self.backend.cache.set(key, avatar, 86400)
+		await self.backend.cache.set(cache_key, avatar, 86400)
 
 		return avatar
 
diff --git a/src/backend/wiki.py b/src/backend/wiki.py
index 7ef21401..9c5f55aa 100644
--- a/src/backend/wiki.py
+++ b/src/backend/wiki.py
@@ -713,6 +713,9 @@ class File(misc.Object):
 	async def get_thumbnail(self, size, format=None):
 		assert self.is_bitmap_image()
 
+		# Let thumbnails live in the cache for up to 24h
+		ttl = 24 * 3600
+
 		cache_key = ":".join((
 			"wiki",
 			"thumbnail",
@@ -724,15 +727,25 @@ class File(misc.Object):
 		))
 
 		# Try to fetch the data from the cache
-		thumbnail = await self.backend.cache.get(cache_key)
+		async with await self.backend.cache.pipeline() as p:
+			# Fetch the key
+			await p.get(cache_key)
+
+			# Reset the TTL
+			await p.expire(cache_key, ttl)
+
+			# Execute the pipeline
+			thumbnail, _ = await p.execute()
+
+		# Return the cached value
 		if thumbnail:
 			return thumbnail
 
 		# Generate the thumbnail
 		thumbnail = util.generate_thumbnail(self.blob, size, format=format, quality=95)
 
-		# Put it into the cache for forever
-		await self.backend.cache.set(cache_key, thumbnail)
+		# Put it into the cache for 24h
+		await self.backend.cache.set(cache_key, thumbnail, ttl)
 
 		return thumbnail
 
diff --git a/src/web/users.py b/src/web/users.py
index b27c09a2..bc4e57f9 100644
--- a/src/web/users.py
+++ b/src/web/users.py
@@ -93,15 +93,24 @@ class AvatarHandler(base.BaseHandler):
 			size = 2048
 
 		# Cache key
-		key = "avatar:letter:%s:%s:%s" % ("".join(letters), format or "N/A", size)
+		cache_key = "avatar:letter:%s:%s:%s" % ("".join(letters), format or "N/A", size)
+
+		# Try to fetch the data from the cache
+		async with await self.backend.cache.pipeline() as p:
+			# Fetch the key
+			await p.get(cache_key)
+
+			# Reset the TTL
+			await p.expire(cache_key, 86400)
+
+			# Execute the pipeline
+			avatar, _ = await p.execute()
 
-		# Fetch avatar from the cache
-		avatar = await self.backend.cache.get(key)
 		if not avatar:
 			avatar = self._make_avatar(letters, size=size, **args)
 
 			# Cache for forever
-			await self.backend.cache.set(key, avatar)
+			await self.backend.cache.set(cache_key, avatar, 86400)
 
 		return avatar
 
-- 
2.39.5