Microgem for compiling assets in parallel

parallel_assets_compiler.gemspec

# -*- encoding: utf-8 -*-

Gem::Specification.new do |s|
  s.name        = 'parallel_assets_compiler'
  s.version     = '0.2.0'
  s.platform    = Gem::Platform::RUBY
  s.author      = 'Jorgen Orehoj Erichsen'
  s.email       = 'joe@erichsen.net'
  s.summary     = 'Compile assets in parallel'
  s.description = 'Compile assets in parallel to speed up deployment'

  s.files         = ['parallel_assets_compiler.rb']
  s.require_path  = '.'

  s.add_dependency('parallel')
  s.add_dependency('actionpack')
end

parallel_assets_compiler.rb

# Compile assets in parallel to speed up deployment
#
# Works by monkey patching actionpack from Rails 3.2.5
#
# Use it by adding this to your Gemfile and run bundle install
#
# gem 'parallel_assets_compiler', :git => 'git://gist.github.com/2873091.git'
#
# Inspired by
# https://github.com/steel/sprockets/commit/6327afc3341e34efd1dfdcfad08e3b9d85f7fd4a
# https://github.com/hornairs/sprockets-rails-parallel

require 'sprockets/static_compiler'
require 'parallel'

module Sprockets
  class StaticCompiler

    def compile
      # Collect paths
      logical_paths = []
      env.each_logical_path do |logical_path| 
        if File.basename(logical_path)[/[^\.]+/, 0] == 'index'
          logical_path.sub!(/\/index\./, '.')
        end
      	logical_paths << logical_path if compile_path?(logical_path)
      end

      # Compute!
      results = Parallel.map(logical_paths) do |logical_path|
        if asset = env.find_asset(logical_path)
          [logical_path, write_asset(asset)]
        end
      end

      write_manifest(Hash[results]) if @manifest
    end

  end
end