Add API endpoint to get Geo node information

app/models/geo/project_registry.rb

 class Geo::ProjectRegistry < Geo::BaseRegistry
   validates :project_id, presence: true
+
+  scope :failed, -> { where.not(last_repository_synced_at: nil).where(last_repository_successful_sync_at: nil) }
+  scope :synced, -> { where.not(last_repository_synced_at: nil, last_repository_successful_sync_at: nil) }
 end

app/models/geo_node.rb

 class GeoNode < ActiveRecord::Base
+  Status = Struct.new(:health, :repositories, :repositories_synced, :repositories_failed)
+
   belongs_to :geo_node_key, dependent: :destroy
   belongs_to :oauth_application, class_name: 'Doorkeeper::Application', dependent: :destroy
   belongs_to :system_hook, dependent: :destroy

lib/api/entities.rb

@@ -768,5 +768,12 @@ module API
       expose :id, :message, :starts_at, :ends_at, :color, :font
       expose :active?, as: :active
     end
+
+    class GeoNodeStatus < Grape::Entity
+      expose :health
+      expose :repositories
+      expose :repositories_synced
+      expose :repositories_failed
+    end
   end
 end

lib/api/geo.rb

@@ -28,6 +28,24 @@ module API
         end
       end
 
+      #  Get node information (e.g. health, repos synced, repos failed, etc.)
+      #
+      # Example request:
+      #   GET /geo/status
+      get 'status' do
+        authenticated_as_admin!
+        require_node_to_be_secondary!
+
+        status = GeoNode::Status.new(
+          HealthCheck::Utils.process_checks(['geo']),
+          Project.count,
+          ::Geo::ProjectRegistry.synced.count,
+          ::Geo::ProjectRegistry.failed.count
+        )
+
+        present status, with: Entities::GeoNodeStatus
+      end
+
       # Enqueue a batch of IDs of wiki's projects to have their
       # wiki repositories updated
       #
@@ -82,6 +100,10 @@ module API
       def require_node_to_be_enabled!
         forbidden! 'Geo node is disabled.' unless Gitlab::Geo.current_node.enabled?
       end
+
+      def require_node_to_be_secondary!
+        forbidden! 'Geo node is disabled.' unless Gitlab::Geo.current_node.secondary?
+      end
     end
   end
 end