1 files changed, 49 insertions, 0 deletions
diff --git a/app/services/groups/count_service.rb b/app/services/groups/count_service.rb
new file mode 100644
index 00000000000..2a15ae3bc57
--- /dev/null
+++ b/app/services/groups/count_service.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module Groups
+  class CountService < BaseCountService
+    include Gitlab::Utils::StrongMemoize
+
+    VERSION = 1
+    CACHED_COUNT_THRESHOLD = 1000
+    EXPIRATION_TIME = 24.hours
+
+    attr_reader :group, :user
+
+    def initialize(group, user = nil)
+      @group = group
+      @user = user
+    end
+
+    def count
+      cached_count = Rails.cache.read(cache_key)
+      return cached_count unless cached_count.blank?
+
+      refreshed_count = uncached_count
+      update_cache_for_key(cache_key) { refreshed_count } if refreshed_count > CACHED_COUNT_THRESHOLD
+      refreshed_count
+    end
+
+    def cache_key
+      ['groups', "#{issuable_key}_count_service", VERSION, group.id, cache_key_name]
+    end
+
+    private
+
+    def relation_for_count
+      raise NotImplementedError
+    end
+
+    def cache_options
+      super.merge({ expires_in: EXPIRATION_TIME })
+    end
+
+    def cache_key_name
+      raise NotImplementedError, 'cache_key_name must be implemented and return a String'
+    end
+
+    def issuable_key
+      raise NotImplementedError, 'issuable_key must be implemented and return a String'
+    end
+  end
+end