Add project export API entities

app/models/project.rb

@@ -1567,6 +1567,21 @@ class Project < ActiveRecord::Base
     Dir.glob("#{export_path}/*export.tar.gz").max_by { |f| File.ctime(f) }
   end
 
+  def export_status
+    if export_in_progress?
+      :started
+    elsif export_project_path
+      :finished
+    else
+      :none
+    end
+  end
+
+  def export_in_progress?
+    shared = Gitlab::ImportExport::Shared.new(relative_path: File.join(disk_path, 'work'))
+    File.directory?(shared.export_path)
+  end
+
   def remove_exports
     return nil unless export_path.present?
 

lib/api/entities.rb

@@ -91,6 +91,21 @@ module API
       expose :created_at
     end
 
+    class ProjectExportStatus < ProjectIdentity
+      include ::API::Helpers::RelatedResourcesHelpers
+
+      expose :export_status
+      expose :_links, if: lambda { |project, options| project.export_status == :finished } do
+        expose :api_url do |project|
+          expose_url(api_v4_projects_export_download_path(id: project.id))
+        end
+
+        expose :web_url do |project|
+          Gitlab::Routing.url_helpers.download_export_project_url(project)
+        end
+      end
+    end
+
     class ProjectImportStatus < ProjectIdentity
       expose :import_status