add API and spec

lib/api/geo_nodes.rb

@@ -77,6 +77,32 @@ module API
 
         present status, with: ::GeoNodeStatusEntity
       end
+
+      # Get project registry failures for the current Geo node
+      #
+      # Example request:
+      #   GET /geo_nodes/:id/failures/:type
+      desc 'Get project registry failures for the current Geo node' do
+        success Entities::GeoNode
+      end
+      params do
+        requires :id, type: Integer, desc: 'The ID of the node'
+        optional :type, type: String, desc: 'Type of failure (repository/wiki)'
+        use :pagination
+      end
+      get ':id/failures/:type' do
+        unless Gitlab::Geo.current_node.id == params[:id]
+          forbidden!('Geo node is not the current node.')
+        end
+
+        geo_node = GeoNode.find(params[:id])
+
+        not_found('Geo node not found') unless geo_node
+
+        project_registries = geo_node.project_registries
+
+        present project_registries, with: ::ProjectRegistryEntity
+      end
     end
   end
 end

spec/requests/api/geo_nodes_spec.rb

@@ -86,4 +86,25 @@ describe API::GeoNodes, :geo, api: true do
       expect(response.status).to eq 403
     end
   end
+
+  describe 'GET /geo_nodes/:id/failures/:type' do
+    it 'fetches the current node failures' do
+      create(:geo_project_registry, :sync_failed)
+      create(:geo_project_registry, :sync_failed)
+
+      stub_current_geo_node(secondary)
+      expect(GeoNode).to receive(:find).and_return(secondary)
+
+      get api("/geo_nodes/#{secondary.id}/failures", admin)
+
+      expect(response.status).to eq 200
+      expect(response.body).to eq('')
+    end
+
+    it 'denies access if not admin' do
+      get api('/geo_nodes', user)
+
+      expect(response.failures).to eq 403
+    end
+  end
 end