Merge remote-tracking branch 'upstream/master' into pipeline-notifications

* upstream/master: (43 commits)
  Disable warming of the asset cache in Spinach tests under CI
  Trim project_path whitespace on form submit
  added skipped definition
  updated some links in definitions
  Don't use Hash#slice since it's not supported in Ruby 2.1
  Create protected branches bundle
  [ci skip] Add a comment explaining validate_board_limit callback
  Fix: Backup restore doesn't clear cache
  Fix GitLab project import when a user has access only to their default namespace.
  Test GitLab project import for a user with only their default namespace.
  We want to release this in 8.13.0
  Add CHANGELOG.md entry
  Return truncation for notification descriptions, fix minor bugs with rendering
  Use guard clause instead of if-else statement
  Tests for markdown HipChat notifications
  Clean up Banzai HTML for HipChat
  Ensure absolute URLs for single lines from Banzai for HipChat
  Absolute URLs for Banzai HTML for HipChat
  Also render commit titles in HipChat notifications
  Full Banzai rendering for HipChat notifications
  ...

1 files changed, 27 insertions, 0 deletions

diff --git a/app/workers/project_cache_worker.rb b/app/workers/project_cache_worker.rb
index ccefd0f71a0..0d524e88dc3 100644
--- a/app/workers/project_cache_worker.rb
+++ b/app/workers/project_cache_worker.rb
@@ -1,9 +1,30 @@
+# Worker for updating any project specific caches.
+#
+# This worker runs at most once every 15 minutes per project. This is to ensure
+# that multiple instances of jobs for this worker don't hammer the underlying
+# storage engine as much.
 class ProjectCacheWorker
   include Sidekiq::Worker
 
   sidekiq_options queue: :default
 
+  LEASE_TIMEOUT = 15.minutes.to_i
+
   def perform(project_id)
+    if try_obtain_lease_for(project_id)
+      Rails.logger.
+        info("Obtained ProjectCacheWorker lease for project #{project_id}")
+    else
+      Rails.logger.
+        info("Could not obtain ProjectCacheWorker lease for project #{project_id}")
+
+      return
+    end
+
+    update_caches(project_id)
+  end
+
+  def update_caches(project_id)
     project = Project.find(project_id)
 
     return unless project.repository.exists?
@@ -15,4 +36,10 @@ class ProjectCacheWorker
       project.repository.build_cache
     end
   end
+
+  def try_obtain_lease_for(project_id)
+    Gitlab::ExclusiveLease.
+      new("project_cache_worker:#{project_id}", timeout: LEASE_TIMEOUT).
+      try_obtain
+  end
 end