Call method when defining Ruby constant

Updater.rb

class Updater
  METADATA_FILE = self.class.file_path
  
  def initialize
    METADATA_FILE
  end
  
  def self.file_path
    'some file path'
  end
end

Updater.new # => 
# ~> -:2:in `<class:Updater>': undefined method `file_path' for Class:Class (NoMethodError)
# ~> 	from -:1:in `<main>'

How can I call the file_path method when defining the METADATA_FILE constant?