discourse/app/controllers/admin/dashboard_controller.rb

require 'disk_space'
class Admin::DashboardController < Admin::AdminController
  def index
    dashboard_data = AdminDashboardData.fetch_cached_stats || Jobs::DashboardStats.new.execute({})
    dashboard_data.merge!(version_check: DiscourseUpdates.check_version.as_json) if SiteSetting.version_checks?

    dashboard_data[:disk_space] = DiskSpace.cached_stats
    render json: dashboard_data
  end

  def problems
    render_json_dump(problems: AdminDashboardData.fetch_problems)
  end
end