From d4d0740e24315e7071f90b3744377b3ca3b5816a Mon Sep 17 00:00:00 2001
From: Andreas Brandl <abrandl@gitlab.com>
Date: Fri, 23 Feb 2018 20:56:43 +0100
Subject: [PATCH] Cache project/user combinations.

---
 app/models/user_contributed_projects.rb       | 22 ++++++++++++++++---
 spec/models/user_contributed_projects_spec.rb |  7 +++---
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/app/models/user_contributed_projects.rb b/app/models/user_contributed_projects.rb
index 846d77f3c69..e051e75af1d 100644
--- a/app/models/user_contributed_projects.rb
+++ b/app/models/user_contributed_projects.rb
@@ -5,9 +5,25 @@ class UserContributedProjects < ActiveRecord::Base
   validates :project, presence: true
   validates :user, presence: true
 
+  CACHE_EXPIRY_TIME = 1.day
+
   def self.track(event)
-    find_or_create_by!(project: event.project, user: event.author)
-  rescue ActiveRecord::RecordNotUnique
-    retry
+    attributes = {project_id: event.project_id, user_id: event.author_id}
+
+    cached_exists?(attributes) do
+      begin
+        find_or_create_by!(attributes)
+        true # not caching the whole record here for now
+      rescue ActiveRecord::RecordNotUnique
+        retry
+      end
+    end
+  end
+
+  private
+
+  def self.cached_exists?(project_id:, user_id:, &block)
+    cache_key = "user_contributed_projects:#{project_id}:#{user_id}"
+    Rails.cache.fetch(cache_key, expires_in: CACHE_EXPIRY_TIME, &block)
   end
 end
diff --git a/spec/models/user_contributed_projects_spec.rb b/spec/models/user_contributed_projects_spec.rb
index 5b8c61750b3..b0a10ca59ab 100644
--- a/spec/models/user_contributed_projects_spec.rb
+++ b/spec/models/user_contributed_projects_spec.rb
@@ -12,16 +12,17 @@ describe UserContributedProjects do
         it 'creates a record' do
           expect { subject }.to change { UserContributedProjects.count }.from(0).to(1)
         end
-
       end
     end
 
     it 'sets project accordingly' do
-      expect(subject.project).to eq(event.project)
+      subject
+      expect(UserContributedProjects.first.project).to eq(event.project)
     end
 
     it 'sets user accordingly' do
-      expect(subject.user).to eq(event.author)
+      subject
+      expect(UserContributedProjects.first.user).to eq(event.author)
     end
 
     it 'only creates a record once per user/project' do