From a36e3720868f3f93e7f23886da3ea32505d2180a Mon Sep 17 00:00:00 2001
From: uu59 <k@uu59.org>
Date: Wed, 19 Nov 2014 15:10:43 +0900
Subject: [PATCH] Add NOTE for cache design

---
 app/models/fluent_gem.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/app/models/fluent_gem.rb b/app/models/fluent_gem.rb
index 10b6c53..15ed629 100644
--- a/app/models/fluent_gem.rb
+++ b/app/models/fluent_gem.rb
@@ -13,7 +13,10 @@ module FluentGem
     end
 
     def list
-      Rails.cache.fetch(LIST_CACHE_KEY) do
+      # NOTE: gem list is heavyly used from anywhere in 1 request, if not caching, user experience to be bad
+      #       but long living caching causes mismatch with actual status e.g. user install plugin from console (without fluentd-ui)
+      #       So our decision is that cache `gem list` in 3 seconds
+      Rails.cache.fetch(LIST_CACHE_KEY, expires_in: 3.seconds) do
         output = `#{gem} list`
         unless $?.exitstatus.zero?
           raise GemError, "failed command: `#{gem} list`"