a capistrano recipe to install rubies using rbenv (for debian/ubuntu)

rbenv-recipes.rb

namespace(:rbenv) {
  _cset(:rbenv_path) {
    capture("echo $HOME/.rbenv").chomp()
  }
  _cset(:rbenv_bin) {
    File.join(rbenv_path, 'bin', 'rbenv')
  }
  _cset(:rbenv_cmd) { # to use custom rbenv_path, we use `env` instead of cap's default_environment.
    path = "#{rbenv_path}/bin:#{rbenv_path}/shims:$PATH"
    "env PATH=#{path.dump()} #{rbenv_bin}"
  }
  _cset(:rbenv_repository, 'git://github.com/sstephenson/rbenv.git')
  _cset(:rbenv_branch, 'master')

  _cset(:rbenv_use_plugins, true)
  _cset(:rbenv_plugins, {
    'ruby-build' => 'git://github.com/sstephenson/ruby-build.git',
  })
  _cset(:rbenv_plugins_options, {
    'ruby-build' => {:branch => 'master'},
  })
  _cset(:rbenv_plugins_path) {
    File.join(rbenv_path, 'plugins')
  }

  _cset(:rbenv_git) {
    if scm == :git
      if fetch(:scm_command, :default) == :default
        fetch(:git, 'git')
      else
        scm_command
      end
    else
      fetch(:git, 'git')
    end
  }

  _cset(:rbenv_ruby_version, '1.9.3-p194')
  _cset(:rbenv_ruby_dependencies, %w(build-essential libreadline6-dev zlib1g-dev libssl-dev bison))

  _cset(:rbenv_use_bundler, true)
  set(:bundle_cmd) { # override bundle_cmd in "bundler/capistrano"
    rbenv_use_bundler ? "#{rbenv_cmd} exec bundle" : 'bundle'
  }

  desc("Setup rbenv.")
  task(:setup, :except => { :no_release => true }) {
    dependencies
    update
    configure
    build
    setup_bundler if rbenv_use_bundler
  }
  after 'deploy:setup', 'rbenv:setup'

  def _rbenv_sync(repository, destination, revision)
    git = rbenv_git
    remote = 'origin'
    verbose = "-q"
    run((<<-E).gsub(/\s+/, ' '))
      if test -d #{destination}; then
        cd #{destination} && #{git} fetch #{verbose} #{remote} && #{git} fetch --tags #{verbose} #{remote} && #{git} merge #{verbose} #{remote}/#{revision};
      else
        #{git} clone #{verbose} #{repository} #{destination} && cd #{destination} && #{git} checkout #{verbose} #{revision};
      fi;
    E
  end

  desc("Update rbenv installation.")
  task(:update, :except => { :no_release => true }) {
    _rbenv_sync(rbenv_repository, rbenv_path, rbenv_branch)
    plugins.update if rbenv_use_plugins
  }

  desc("Purge rbenv.")
  task(:purge, :except => { :no_release => true }) {
    run("rm -rf #{rbenv_path}")
  }

  namespace(:plugins) {
    desc("Update rbenv plugins.")
    task(:update, :except => { :no_release => true }) {
      rbenv_plugins.each { |name, repository|
        options = ( rbenv_plugins_options[name] || {})
        branch = ( options[:branch] || 'master' )
        _rbenv_sync(repository, File.join(rbenv_plugins_path, name), branch)
      }
    }
  }

  task(:configure, :except => { :no_release => true }) {
    # nop
  }

  task(:dependencies, :except => { :no_release => true }) {
    unless rbenv_ruby_dependencies.empty? # dpkg-query is faster than apt-get on querying if packages are installed
      run("dpkg-query --show #{rbenv_ruby_dependencies.join(' ')} 2>/dev/null || #{sudo} apt-get -y install #{rbenv_ruby_dependencies.join(' ')}")
    end
  }

  desc("Build ruby within rbenv.")
  task(:build, :except => { :no_release => true }) {
    ruby = fetch(:rbenv_ruby_cmd, 'ruby')
    run("#{rbenv_cmd} whence #{ruby} | grep -q #{rbenv_ruby_version} || #{rbenv_cmd} install #{rbenv_ruby_version}")
    run("#{rbenv_cmd} global #{rbenv_ruby_version} && #{rbenv_cmd} exec #{ruby} --version")
  }

  _cset(:rbenv_bundler_gem, 'bundler')
  task(:setup_bundler, :except => { :no_release => true }) {
    gem = "#{rbenv_cmd} exec gem"
    if v = fetch(:rbenv_bundler_version, nil)
      q = "-n #{rbenv_bundler_gem} -v #{v}"
      f = "grep #{rbenv_bundler_gem} | grep #{v}"
      i = "-v #{v} #{rbenv_bundler_gem}"
    else
      q = "-n #{rbenv_bundler_gem}"
      f = "grep #{rbenv_bundler_gem}"
      i = "#{rbenv_bundler_gem}"
    end
    run("unset -v GEM_HOME; #{gem} query #{q} 2>/dev/null | #{f} || #{gem} install #{i}")
    run("#{rbenv_cmd} rehash && #{bundle_cmd} version")
  }
}

# vim:set ft=ruby ts=2 sw=2 :

current impl cannot use custom rbenv_path.

stopped using default_environment to enable custom rbenv_path.