project-watcher.rb

#!/usr/bin/env ruby
# encoding: utf-8

require "find"
require "eventmachine"

# === Usage ===
# project-watcher.rb --no-daemon  -- run
# project-watcher.rb              -- run as a daemon
# project-watcher.rb --debug      -- run in debug mode

# http://eventmachine.rubyforge.org/EventMachine/FileWatch.html
module FileWatcher
  def file_modified
    rsync path
  end
end

$DEBUG = ARGV.include?("--debug")

def debug(*args)
  puts *args if $DEBUG
end

def reload_files
  debug "Reloading files ..."
  old_files, @files = (@files || Array.new), Array.new
  Find.find(".") do |file|
    if File.file?(file)
      @files << file
      EM.watch_file(file, FileWatcher)
    end
  end

  # create
  newly_created_files = @files - old_files
  newly_created_files.each(&method(:rsync))

  # remove
  removed_files = old_files - @files
  removed_files.each(&method(:un_rsync))
rescue Errno::EMFILE
  # WTF?
end

def rsync(path)
  debug "Pretending to rsync #{path}"
end

def un_rsync(path)
  debug "Pretending to un-rsynch #{path}"
end

#
def main
  trap(:HUP) do
    reload_files
  end

  trap(:KILL) do
    debug "Ending ..."
    EM.stop
  end

  EM.run do
    reload_files

    EventMachine::PeriodicTimer.new(5) do
      reload_files
    end
  end
end

EM.kqueue if EM.kqueue?

#
if __FILE__ == $0 && ! ARGV.include?("--no-daemon")
  pid = fork do
    main
  end

  puts "Starting project watching deamon with PID #{pid}. Send it HUP signal to reload."
else
  main
end