Fix flushing caches when using a GEO secondary

This is not the nicest solution since it duplicates some logic from CE's
"perform" method, but it's the best solution for now.

lib/ee/workers/project_cache_worker.rb

@@ -5,9 +5,9 @@ module EE
     # This module is intended to encapsulate EE-specific methods
     # and be **prepended** in the `ProjectCacheWorker` class.
     module ProjectCacheWorker
-      def update_caches(project_id)
+      def perform(*args)
         if ::Gitlab::Geo.secondary?
-          update_geo_caches(project_id)
+          perform_geo_secondary(*args)
         else
           super
         end
@@ -17,14 +17,12 @@ module EE
 
       # Geo should only update Redis based cache, as data store in the database
       # will be updated on primary and replicated to the secondaries.
-      def update_geo_caches(project_id)
-        project = Project.find(project_id)
+      def perform_geo_secondary(project_id, refresh = [])
+        project = Project.find_by(id: project_id)
 
-        return unless project.repository.exists?
+        return unless project && project.repository.exists?
 
-        if project.repository.root_ref
-          project.repository.build_cache
-        end
+        project.repository.refresh_method_caches(refresh.map(&:to_sym))
       end
     end
   end

spec/workers/project_cache_worker_spec.rb

@@ -52,11 +52,12 @@ describe ProjectCacheWorker do
 
       context 'when in Geo secondary node' do
         before do
-          allow(Gitlab::Geo).to receive(:secondary?) { true }
+          allow(Gitlab::Geo).to receive(:secondary?).and_return(true)
         end
 
         it 'updates only non database cache' do
-          expect_any_instance_of(Repository).to receive(:build_cache).and_call_original
+          expect_any_instance_of(Repository).to receive(:refresh_method_caches).
+            and_call_original
 
           expect_any_instance_of(Project).not_to receive(:update_repository_size)
           expect_any_instance_of(Project).not_to receive(:update_commit_count)