Fix application settings cache not expiring after changes

cache_key is an instance method that relies on updated_at. When changes
were made, the time-dependent key was being used instead of X.application_setting.last.

Closes #3609

1 files changed, 4 insertions, 7 deletions

diff --git a/app/models/ci/application_setting.rb b/app/models/ci/application_setting.rb
index 4e512d290ee..7f5df8ce6c4 100644
--- a/app/models/ci/application_setting.rb
+++ b/app/models/ci/application_setting.rb
@@ -12,17 +12,18 @@
 module Ci
   class ApplicationSetting < ActiveRecord::Base
     extend Ci::Model
+    CACHE_KEY = 'ci_application_setting.last'
 
     after_commit do
-      Rails.cache.write(cache_key, self)
+      Rails.cache.write(CACHE_KEY, self)
     end
 
     def self.expire
-      Rails.cache.delete(cache_key)
+      Rails.cache.delete(CACHE_KEY)
     end
 
     def self.current
-      Rails.cache.fetch(cache_key) do
+      Rails.cache.fetch(CACHE_KEY) do
         Ci::ApplicationSetting.last
       end
     end
@@ -33,9 +34,5 @@ module Ci
         add_pusher: Settings.gitlab_ci['add_pusher'],
       )
     end
-
-    def self.cache_key
-      'ci_application_setting.last'
-    end
   end
 end