From 2db7c5762b41acbcbd71bc4bd5a8aa3d90e1a383 Mon Sep 17 00:00:00 2001 From: Stan Hu Date: Tue, 2 Jul 2019 11:19:30 -0700 Subject: Cache Flipper feature flags in L1 and L2 caches In https://gitlab.com/gitlab-com/gl-infra/production/issues/928, we saw a significant amount of network traffic and CPU usage due to Redis checking feature flags via Flipper. Since these flags are hit with every request, the overhead becomes significant. To alleviate Redis overhead, we now cache the data in the following way: * L1: A thread-local memory store for 1 minute * L2: Redis for 1 hour --- lib/feature.rb | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/feature.rb b/lib/feature.rb index 22420e95ea2..e28333aa58e 100644 --- a/lib/feature.rb +++ b/lib/feature.rb @@ -103,10 +103,27 @@ class Feature feature_class: FlipperFeature, gate_class: FlipperGate) + # Redis L2 cache + redis_cache_adapter = + Flipper::Adapters::ActiveSupportCacheStore.new( + active_record_adapter, + l2_cache_backend, + expires_in: 1.hour) + + # Thread-local L1 cache: use a short timeout since we don't have a + # way to expire this cache all at once Flipper::Adapters::ActiveSupportCacheStore.new( - active_record_adapter, - Rails.cache, - expires_in: 1.hour) + redis_cache_adapter, + l1_cache_backend, + expires_in: 1.minute) + end + + def l1_cache_backend + Gitlab::ThreadMemoryCache.cache_backend + end + + def l2_cache_backend + Rails.cache end end -- cgit v1.2.1