def serial_task(name, options = {}, &block)
  servers = self.roles[options[:roles]].collect {|server| server.host}
  task_syms = []
  servers.each do |hostname|
    role_sym = "_serial_task_#{name.to_s}_#{hostname}".to_sym
    task_sym = "_do_task_#{name.to_s}_#{hostname}".to_sym
    task_syms << task_sym
    role role_sym, hostname
    task task_sym, :roles => role_sym, &block
  end
  task name do
    task_syms.each do |t|
      self.send t
    end
  end
end

serial_task :pwd, :roles => web do
  run "pwd"
end

#!/usr/bin/env ruby

require 'yaml'
require 'rubygems'
require_gem 'net-ssh'

$stdout.sync = true

def help
  puts <<-USAGE
This tool allows you to conviniently deploy your projects on production
or staging servers.

  Useage:
    deploy <target>
    Please specify configuration in ~/.deployrc
    
  Example:  
    
    example ~/.deployrc:   
    
      hieraki:
        server: linux
        get: svn export svn://myserver/hieraki/trunk
        directory: /var/www/applications/hieraki
        test: RAILS_ENV=production rake

        after_test:
          - chmod 777 log/
          - chmod 666 log/*

        after_commit:
          - sudo /etc/init.d/apache reload    

  Note: 
  
    server, get and directory are required
    
    available hooks are
      - after_connect
      - after_deploy
      - after_test
      - after_commit
        
  USAGE
  exit
end

def do_exec(cmd)
  print "\n\n  #{cmd}\n    "
  
  stderr = ""
  $session.process.open( cmd ) do |cmd|
    cmd.on_exit do |p, status|
      if status == 0
        print "[done]\n" 
      else
        puts "    #{stderr}"        
        print "[failed]\n" 
        exit
      end
    end
    
    cmd.on_stderr do |p, data|
      stderr << data.gsub(/\n/, "\n    ")
    end    
    cmd.on_stdout do |p, data|
      STDOUT << data.gsub(/\n/, "\n    ")
    end                
  end  
end

# Batch jobs

def deploy
  puts      "\ndeploying"  

  print     "  creating dirs"
  do_exec   "mkdir -p #{$config['directory']}" 

  print     "  get"
  do_exec   "#{$config['get']} #{$config['deploy']}"
end

def test
  puts      "\ntesting"  
  do_exec   "cd #{$config['deploy']}; #{$config['test']}"
end

def commit
  puts      "\ncomitting"
  print     "  creating new link"
  do_exec   "ln -nfs #{$config['deploy']}/ #{$config['target']}"
end

def run_tasks(tasks)
  $config[tasks].to_a.each do |task|    
    do_exec "cd #{$config['deploy']}; #{task}" 
  end
end


app_name = ARGV[0] || help
$config = YAML::load(File.open(File.expand_path("~/.deployrc")))[app_name]

# compute deploy directory 
$config['deploy'] = $config['directory'] + "/#{Time.now.strftime("%Y%m%d-%H%M")}"
# compute target directory 
$config['target'] = $config['directory'] + "/latest"

puts "deploying #{app_name} to #{$config["server"]}"

$session = Net::SSH.start( $config["server"] )

run_tasks("after_connect")  
deploy
run_tasks("after_deploy")
test
run_tasks("after_test")
commit
run_tasks("after_commit")
puts ""
puts "success!"