You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: diagnostic.rb
    path of file: ./repos/expertiza/config
    
    the code of the file until where you have to start completion: module MyApp
  # Logger to sit between test and server end. When usin
    
    def call(env)
      @app.call(env)
    rescue StandardError => e
      trace = e.backtrace.select { |l| l.start_with?(Rails.root.to_s) }.join("\n    ")
      msg = "#{e.class}\n#{e.message}\n#{trace}\n"
      File.open(FILENAME, 'a') { |f| f.write msg }
      raise e
    end