README

This example shows how to use a DRb client/server 
with buildr 1.3.3. 
Invoke this file the first time with a --drb flag
to start the server. If no --drb flag is present
we connect to the server.
Features:
 - Execution of tasks on a previously loaded buildfile
  - buildfile reloading if modified.#  - NO CLIENT OUTPUT redirection is implemented.

buildfile

#!/usr/bin/env ruby
exit !!!eval(DATA.read, binding) if $0 == __FILE__

repositories.remote << "http://repo1.maven.org/maven2"
define('foo') do
  
  project.version = '1.3.3'
  puts "Defined project Foo"
  @time = 0
  task('hello') { puts "Hello world #{@time += 1} time!" }
  task('bye') do
    $stderr.print "Your name? "
    name = $stdin.gets; puts "See ya #{name}"
  end

  define('bar') do
    package(:jar)
  end
  
end

__END__

require File.expand_path('dbuildr', File.dirname(__FILE__))

dbuildr.rb

#!/usr/bin/env ruby
$:.push '/home/vic/hk/buildr/lib', '/home/vic/hk/buildr/addon' # for testing on vic env.

require 'drb'

PORT = 9876

begin

  buildr = DRbObject.new(nil, "druby://:#{PORT}")
  buildr.remote_ping # test if the server is running
  DRb.start_service("druby://:#{PORT + 1}")
  buildr.remote_run Dir.pwd, $stdin, $stdout, $stderr, ARGV

rescue DRb::DRbConnError => e
  
  require 'rubygems'
  gem 'rake', '>=0.8.3'
  require 'buildr'
  
  module DistributedBuildr
    
    # save the tasks,rules,layout defined by buildr
    # based on the code from the sandbox
    @tasks = Buildr.application.tasks.collect do |original|
      prerequisites = original.send(:prerequisites).map(&:to_s)
      actions = original.instance_eval { @actions }.clone
      lambda do
        original.class.send(:define_task, original.name=>prerequisites).tap do |task|
          task.comment = original.comment
          actions.each { |action| task.enhance &action }
        end
      end
    end
    @rules = Buildr.application.instance_variable_get(:@rules)
    @layout = Layout.default.clone

    class << self
      attr_accessor :tasks, :rules, :layout
    end

    def remote_ping
      true # tell the client we are alive
    end

    def remote_run(original_dir, stdin, stdout, stderr, argv)
      $stdin, $stdout, $stderr = stdin, stdout, stderr
      ARGV.replace argv
      @original_dir = original_dir
      init 'Distributed Buildr'
      if @rakefile
        if !@last_loaded || buildfile.timestamp > @last_loaded
          # buildfile updated, need to reload
          Project.clear
          @tasks = {}
          DistributedBuildr.tasks.each { |block| block.call }
          @rules = DistributedBuildr.rules.clone
          Layout.default = DistributedBuildr.layout.clone
          load_buildfile
          @last_loaded = buildfile.timestamp
        else
          clear_invoked_tasks
        end
      else
        load_buildfile
        @last_loaded = buildfile.timestamp
      end      
      top_level
    end
      
    def clear_invoked_tasks
      lookup('buildr:initialize').instance_eval do 
        @already_invoked = false
        @actions = []
      end
      projects = Project.instance_variable_get(:@projects) || {}
      @tasks.each_pair do |name, task|
        is_project = projects.key?(task.name)
        task.instance_variable_set(:@already_invoked, false) unless is_project
      end
    end

  end # DistribuitedBuildr
  
  class Buildr::Application; include DistributedBuildr; end
  DRb.start_service("druby://:#{PORT}", Buildr.application)
  puts "DistribuitedBuildr waiting for invocation on port #{PORT}."

  DRb.thread.join

end