title: converting capistrano v2 deploy.rb to capistrano v3 deploy.rb
body: <p>Trying to confer this block of code to the version 3 of capistrano to no avail. Everything is so changed. Anyone can help me on the right track to convert it ?</p>
  
  <p><strong>Old version 2 deploy.rb:</strong></p>
  
  <pre><code>#require 'new_relic/recipes'
  require 'bundler/capistrano'
  require './config/boot'
  require 'whenever/capistrano'
  require 'rvm/capistrano'
  require 'bundler/capistrano'
  require 'puma/capistrano'
  
  
  set :application, "books"
  set :whenever_command, "bundle exec whenever"
  set :rvm_type, :system
  set :rvm_ruby_string, ENV['GEM_HOME'].gsub(/.*\//,'')
  set :scm, :git
  set :repository, "/srv/books.git"
  
  set :bundle_flags, "--deployment --binstubs"
  set (:bundle_cmd) { "#{release_path}/bin/bundle" }
  
  set :branch, "master"
  set :migrate_target, :current
  set :ssh_options, {:forward_agent =&gt; true}
  set :rails_env, "production"
  set :deploy_to, "/srv/books"
  set :normalize_asset_timestamps, false
  
  set :keep_releases, 5
  after "deploy:update", "deploy:cleanup"
  #, "deploy:eye:stop", "deploy:eye:start"
  
  
  set :user, "root"
  set :group, ""
  set :use_sudo, false
  default_run_options[:pty] = true
  
  #set :port, 5984
  #ssh_options[:port] = 5984
  set :port, 22
  ssh_options[:port] = 22
  
  role :web,  "x"
  role :app,  "x"
  role :db,   "x", :primary =&gt; true
  
  set(:latest_release) { fetch(:current_path) }
  set(:release_path) { fetch(:current_path) }
  set(:current_release) { fetch(:current_path) }
  
  set(:current_revision) { capture("cd #{current_path}; git rev-parse --short HEAD").strip }
  set(:latest_revision) { capture("cd #{current_path}; git rev-parse --short HEAD").strip }
  set(:previous_revision) { capture("cd #{current_path}; git rev-parse --short HEAD@{1}").strip }
  
  default_environment["RAILS_ENV"] = 'production'
  
  #before :deploy, 'pgsql:backup'#, "deploy:rvm:trust_rvmrc"
  load 'config/recipes/asset_pipeline.cap'
  load 'config/recipes/database.cap'
  load 'config/recipes/misc'
  #load 'config/recipes/performance'
  load 'config/recipes/rvm'
  load 'config/recipes/web.cap'
  load 'config/recipes/eye.cap'
  
  #new relic
  #after "deploy", "newrelic:notice_deployment"
  #after "deploy:update", "newrelic:notice_deployment"
  #after "deploy:migrations", "newrelic:notice_deployment"
  #after "deploy:cold", "newrelic:notice_deployment"
  
  namespace :deploy do
  
    desc "Deploy your application"
    task :default do
      cleanlog
      update
      migrate
      #sitemap
      restart_nginx
    end
  
    desc "Setup your git-based deployment app."
    task :setup, :except =&gt; {:no_release =&gt; true} do
      dirs = [deploy_to, shared_path]
      dirs += shared_children.map { |d| File.join(shared_path, d) }
      run "#{try_sudo} mkdir -p #{dirs.join(' ')} &amp;&amp; #{try_sudo} chmod g+w #{dirs.join(' ')}"
      run "git clone #{repository} #{current_path}"
    end
  
    task :cold do
      update
      migrate
    end
  
    desc "Update the deployed code."
    task :update_code, :except =&gt; {:no_release =&gt; true} do
      run "cd #{current_path}; git fetch origin; git reset --hard #{branch}"
      finalize_update
    end
  
    desc "Update the database (overwritten to avoid symlink)"
    task :migrations do
      transaction do
        update_code
      end
      migrate
      restart
    end
  
    task :finalize_update, :except =&gt; {:no_release =&gt; true} do
      run "chmod -R g+w #{latest_release}" if fetch(:group_writable, true)
  
      # mkdir -p is making sure that the directories are there for some SCM's that don't
      # save empty folders
      # ln -sf #{shared_path}/database.yml #{latest_release}/config/database.yml
      run &lt;&lt;-CMD
        rm -rf #{latest_release}/log #{latest_release}/public/system #{latest_release}/tmp/pids &amp;&amp;
        mkdir -p #{latest_release}/public &amp;&amp;
        mkdir -p #{latest_release}/tmp &amp;&amp;
        ln -s #{shared_path}/log #{latest_release}/log &amp;&amp;
        ln -s #{shared_path}/system #{latest_release}/public/system &amp;&amp;
        ln -s #{shared_path}/pids #{latest_release}/tmp/pids
  
      CMD
  
      if fetch(:normalize_asset_timestamps, true)
        stamp = Time.now.utc.strftime("%Y%m%d%H%M.%S")
        asset_paths = fetch(:public_children, %w(images stylesheets javascripts)).map { |p| "#{latest_release}/public/#{p}" }.join(" ")
        run "find #{asset_paths} -exec touch -t #{stamp} {} ';'; true", :env =&gt; {"TZ" =&gt; "UTC"}
      end
    end
  
    desc "Zero-downtime restart of Unicorn"
    task :restart, :except =&gt; {:no_release =&gt; true} do
      run "#{try_sudo} touch #{File.join(current_path, 'tmp', 'restart.txt')}"
      run "kill -s USR2 `cat /srv/books/shared/tmp/pids/unicorn.pid`"
      deploy.eye.stop
      deploy.eye.start
    end
  
    desc "reload the database with seed data"
    task :seed do
      run "cd #{current_path}; bundle exec rake db:seed RAILS_ENV=#{rails_env}"
    end
  
    namespace :rollback do
      desc "Moves the repo back to the previous version of HEAD"
      task :repo, :except =&gt; {:no_release =&gt; true} do
        set :branch, "HEAD@{1}"
        deploy.default
      end
  
      desc "Rewrite reflog so HEAD@{1} will continue to point to at the next previous release."
      task :cleanup, :except =&gt; {:no_release =&gt; true} do
        run "cd #{current_path}; git reflog delete --rewrite HEAD@{1}; git reflog delete --rewrite HEAD@{1}"
      end
  
      desc "Rolls back to the previously deployed version."
      task :default do
        rollback.repo
        rollback.cleanup
      end
    end
  end
  
  def run_rake(cmd)
    run "cd #{current_path}; #{rake} #{cmd}"
  end
  </code></pre>
  
  <p><strong>New version V3 deploy.rb:</strong></p>
  
  <pre><code>set :application, 'books'
  set :repo_url, 'root@prod:srv/books.git'
  
  # ask :branch, proc { `git rev-parse --abbrev-ref HEAD`.chomp }
  
  # set :deploy_to, '/var/www/my_app'
  # set :scm, :git
  
  # set :format, :pretty
  # set :log_level, :debug
  # set :pty, true
  
  # set :linked_files, %w{config/database.yml}
  # set :linked_dirs, %w{bin log tmp/pids tmp/cache tmp/sockets vendor/bundle public/system}
  
  # set :default_env, { path: "/opt/ruby/bin:$PATH" }
  # set :keep_releases, 5
  
  namespace :deploy do
  
    desc 'Restart application'
    task :restart do
      on roles(:app), in: :sequence, wait: 5 do
        # Your restart mechanism here, for example:
        # execute :touch, release_path.join('tmp/restart.txt')
      end
    end
  
    after :restart, :clear_cache do
      on roles(:web), in: :groups, limit: 3, wait: 10 do
        # Here we can do anything such as:
        # within release_path do
        #   execute :rake, 'cache:clear'
        # end
      end
    end
  
    after :finishing, 'deploy:cleanup'
  
  
    ## CUSTOM NEEDS UPDATE
    desc "Clearing the production log"
    task :cleanlog do
      run "cd #{current_path}; rake log:clear"
    end
  
    desc "Refresh the sitemap."
    task :sitemap do
      run "cd #{current_path}; rake sitemap:refresh"
    end
  
    task :update do
      transaction do
        update_code
      end
    end
  
  end
  </code></pre>