rake pipeline rack config

config.ru

require 'bundler/setup'
require 'sass'
require 'compass'
require 'rake-pipeline'
require 'listen'
require 'rack/lock'
require 'ruby-debug'
require 'securerandom'

STDOUT.sync = true

root = File.expand_path File.dirname(__FILE__)
project = Rake::Pipeline::Project.new(File.join(root, 'Assetfile'))
#project.invoke_clean

cache_manifest_path = File.join(root, 'assets', 'cache.manifest')

require 'thread'
build_lock = Mutex.new

build_proc = lambda {|modified, added, removed|
  build_lock.synchronize {
    puts 'FILE CHANGE'
    puts '  modified: ' + modified.join(', ') unless modified.empty?
    puts '  added: ' + added.join(', ') unless added.empty?
    puts '  removed: ' + removed.join(', ') unless removed.empty?
    start = Time.now
    if added.size > 0 || removed.size > 0
      puts "BUILD (CLEAN) #{start}"
      begin
        project.invoke_clean
      rescue
        puts "ERROR: #{$!.inspect}"
      end
    else
      puts "BUILD #{start}"
      begin
        project.invoke
      rescue
        puts "ERROR: #{$!.inspect}"
      end
    end
    cache_manifest = File.read(cache_manifest_path)
    cache_manifest.sub!(/Fingerprint:\ .+$/, "Fingerprint: #{SecureRandom.hex(16)}")
    open(cache_manifest_path, 'w') {|f| f.write(cache_manifest)}
    puts "FINISHED #{Time.now.to_i - start.to_i} seconds"
  }
}

listen_paths = ['app', 'css', 'images']
queue = Queue.new
listen_paths.each do |listen_path|
  listen_path = File.join(root, listen_path)
  Thread.new do 
    listener = Listen.to(listen_path)
    listener.change(&build_proc)
    queue << listen_path
    listener.start # enter the run loop
  end
end
listen_paths.size.times do
  puts "watching #{queue.pop}"
end

use Rack::Lock, build_lock
run Rack::File.new(root)