use Rails::CurrentAttributes with current_user

application_controller.rb

# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
  before_action :set_current_user
  private def set_current_user
    Current.user = current_user
  end
end

application_helper.rb

module ApplicationHelper
   def current_user
     Current.user || super
   end
end

current.rb

# app/models/current.rb
class Current < ActiveSupport::CurrentAttributes
  attribute :user
end

note that when rendering outside a controller you'll have to manually set Current.user in your job/channel/etc