Rakefile task for Puma with Rerun

Rakefile.rb

require 'bundler/setup'

namespace :server do
  desc 'Start the Puma webserver in development mode (rerun, debug).'
  task :debug do
    # Delay requiring these to avoid Rake failures in production.
    require 'file-tail'
    require 'rerun'
    require 'tempfile'

    class Rerun::PumaRunner < Rerun::Runner
      alias_method :stop_without_signal, :stop

      def stop_with_signal(signal = nil)
        _signal = @options[:signal]
        @options[:signal] = signal
        stop_without_signal
        @options[:signal] = _signal
      end

      alias_method :stop, :stop_with_signal
    end

    rerun_options = %w'--restart --signal USR2' # or USR1 for phased restarts
    rerun_command = 'puma --debug --quiet' \
      ' --redirect-stdout %<stdout>s' \
      ' --redirect-stderr %<stderr>s' \
      ' --redirect-append'

    fail 'Must run task from top-level directory' \
      unless Dir.pwd == __dir__

    # Redirect Puma output to prevent errors writing to non-existent TTY.
    tmpfile = Tempfile.new %w[rerun-puma- .log]
    last_line = -1

    at_exit do
      # Make sure we show all lines of Puma output if the TTY is still there.
      File.open(tmpfile) do |logfile|
        logfile.extend File::Tail
        logfile.return_if_eof = true
        logfile.forward last_line + 1
        logfile.tail { |line| puts line }
      end

      # Close and delete the temporary file.
      tmpfile.close!
    end

    runner = Rerun::PumaRunner.new \
      rerun_command % {
        :stdout => tmpfile.path,
        :stderr => tmpfile.path
      },
      Rerun::Options.parse(rerun_options)

    trap 'SIGHUP' do
      unless $stdin.tty? and not $stdin.closed?
        # Prevent Ruby from trying to write to the now non-existent TTY.
        [$stdout, $stderr].each { |fd| fd.reopen(File::NULL, 'w') }
      end

      runner.stop
      exit false
    end

    runner.start
    runner.join # this does not block

    File.open(tmpfile) do |logfile|
      logfile.extend File::Tail
      logfile.interval = 10
      logfile.tail do |line|
        last_line += 1
        puts line
      end
    end
  end
end

This is a lot of code for something ostensibly simple:

1. Start Puma with rerun.
2. Have rerun use SIGUSR2 to tell Puma when to restart the workers to pull in changes.
3. Gracefully (and quickly) shutdown Puma when the user enters 'x' or 'q' or Ctrl-C.
4. Gracefully shutdown Puma if the terminal suddenly disconnects.
5. Show the user all of the expected output (and error messages) from Puma and rerun.

You'd think, "Just rerun -- puma, right?" Unfortunately, a lot of these things are mutually exclusive due to the way rerun works with a custom signal, quirks in the way Puma forks processes, spawns threads, and dups file descriptors, and Ruby's tendency to raise exceptions when stdout and/or stderr go away (exceptions that are raised from deep within rerun and Puma and therefore difficult for the humble user to catch and handle while still terminating things gracefully).

Again, the above is a lot of code, but it meets all of my requirements. Suggestions welcome.