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      = 'Jørgen Orehøj Erichsen'
  s.email       = '[email protected]'
  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

Cut my assets compilation time from 1m13secs to 53 secs on a Mac i5 Dual SSD machine.

And from 95.5 secs to 57.3 secs on Heroku. That's awesome. Thanks @joerichsen for the awesome gem and @brendtd for the correction

Undumpable Exception -- #<NoMethodError: undefined method `options=' for true:TrueClass>
/Users/kain/.rvm/gems/ruby-1.9.3-p194/gems/parallel-0.5.18/lib/parallel.rb:173:in `work_in_processes'
/Users/kain/.rvm/gems/ruby-1.9.3-p194/gems/parallel-0.5.18/lib/parallel.rb:55:in `map'

same issue Undumpable Exception -- #<NoMethodError: undefined method `options=' for true:TrueClass>

I get this w/ sprockets 2.2.2:

undefined method `compile_path?' for #<Sprockets::StaticCompiler:0x007fa14f4fc048>
/Users/user/bundle/ruby/1.9.1/bundler/gems/2873091-2e1e123a0036/parallel_assets_compiler.rb:26:in `block in compile'

Looks like that method may have been removed from actionpack? I tried this one from turbo-sprockets-rails3:

      private
      def compile_path?(logical_path)
        paths.each do |path|
          case path
          when Regexp
            return true if path.match(logical_path)
          when Proc
            return true if path.call(logical_path)
          else
            return true if File.fnmatch(path.to_s, logical_path)
          end
        end
        false
      end

It worked fine on my dev box, but on my build agent I got the Undumpable Exception :(

Make it a real gem!

Doesn't work with compile_path? error.

Make it a real gem!