Rakefile

##################################################################################
# Deploy
# Awesome deploy script stolen from:
#  http://glu.ttono.us/articles/2008/04/05/really-simple-git-deployment-with-vlad
##################################################################################

begin
  require 'rake_remote_task'

  APP_NAME = "someapp"
  DEPLOY_ROOT = "/usr/local/share/applications/#{APP_NAME}"
  ON_DEPLOY_RESTART = ["someappd"]

  role :app_server, "myserver.com"

  def archive
    commit = `git-rev-list --max-count=1 --abbrev=10 --abbrev-commit HEAD`.chomp
    file = "#{APP_NAME}-#{commit}.tar.gz"
  end

  def restart_daemons
    ON_DEPLOY_RESTART.each do |app|
      run "sudo god restart #{app}"
    end
  end

  namespace :deploy do
    task :build do
      sh "git archive --format=tar HEAD | gzip > #{archive}"
    end

    remote_task :push => :build do
      rsync archive, "/tmp"
    end

    desc "Install a release from the latest commit"
    remote_task :install => :push do
      date_stamp = Time.now.strftime("%Y%m%d")
      last_release = run("ls #{DEPLOY_ROOT}/rels | sort -r | head -n 1").chomp

      if last_release =~ /#{date_stamp}\-(\d+)/
        serial = $1.to_i + 1
      else
        serial = 0 
      end

      rel = ("%d-%02d" % [date_stamp, serial])
      rel_dir = "#{DEPLOY_ROOT}/rels/#{rel}"

      run "sudo mkdir -p #{rel_dir}"
      run "sudo tar -xzvf /tmp/#{archive} -C #{rel_dir} && rm -rf /tmp/#{archive}"
      run "sudo ln -s -f -T #{rel_dir} #{DEPLOY_ROOT}/current"
      restart_daemons
    end

    desc "Rollback to the previous release"
    remote_task :rollback do
      current_link = run("ls -alF #{DEPLOY_ROOT} | awk '/current -> .*/ { print $NF }'").chomp
      current = File.basename(current_link)
      releases = run("ls #{DEPLOY_ROOT}/rels | sort -r").split("\n")
      previous = releases.find {|rel| current > rel}
      raise "No previous release" if previous.nil?
      run "sudo ln -s -f -T #{DEPLOY_ROOT}/rels/#{previous} #{DEPLOY_ROOT}/current"
      restart_daemons
      puts "Moved to #{previous}"
    end

    desc "Rollforward to the next release"
    remote_task :rollforward do
      current_link = run("ls -alF #{DEPLOY_ROOT} | awk '/current -> .*/ { print $NF }'").chomp
      current = File.basename(current_link)
      releases = run("ls #{DEPLOY_ROOT}/rels | sort -r").split("\n")
      next_rel = releases.find {|rel| current < rel}
      raise "No next release" if next_rel.nil?
      run "sudo ln -s -f -T #{DEPLOY_ROOT}/rels/#{next_rel} #{DEPLOY_ROOT}/current"
      restart_daemons
      puts "Moved to #{next_rel}"
    end
  end
rescue LoadError => e
  puts "NOTE: Install vlad to get Kevin's awesome deployment tasks"
end