capistrano 3 examples

unicorn.cap

namespace :load do
  task :defaults do
    set :unicorn_bin, :unicorn_rails
    set :unicorn_pid, -> { shared_path.join('tmp', 'pids', 'unicorn.pid') }
    set :unicorn_config, -> { current_path.join('config', 'unicorn.rb') }
    set :unicorn_gemfile, -> { current_path.join('Gemfile') }
    set :unicorn_env, -> { fetch(:rails_env) || fetch(:stage) }
    set :unicorn_roles, :app
    set :unicorn_sleep, 2
  end
end

namespace :unicorn do
  desc 'Start unicorn'
  task :start do
    on roles fetch(:unicorn_roles) do
      within current_path do
        with bundle_gemfile: fetch(:unicorn_gemfile) do
          if test "[ -e #{fetch(:unicorn_pid)} ] && kill -0 #{pid}"
            info 'Unicorn is running...'
          else
            execute fetch(:unicorn_bin), '-D',
              '-c', fetch(:unicorn_config),
              '-E', fetch(:unicorn_env)
          end
        end
      end
    end
  end

  desc 'Stop unicorn (QUIT)'
  task :stop do
    on roles fetch(:unicorn_roles) do
      if test "[ -e #{fetch(:unicorn_pid)} ]"
        if test "kill -0 #{pid}"
          info 'Stopping unicorn...'
          execute :kill, '-s QUIT', pid
        else
          info "Cleaning up dead unicorn pid..."
          execute :rm, fetch(:unicorn_pid)
        end
      else
        info 'Unicorn is not running...'
      end
    end
  end

  desc 'Restart unicorn (USR2 + QUIT); Use this when preload_app: true'
  task :restart do
    invoke 'unicorn:start'
    on roles fetch(:unicorn_roles) do
      with bundle_gemfile: fetch(:unicorn_gemfile) do
        info 'Restarting unicorn...'
        execute :kill, '-s USR2', pid
        execute :sleep, fetch(:unicorn_sleep)
        if test "[ -e #{fetch(:unicorn_pid)}.oldbin ]"
          execute :kill, '-s QUIT', pid_oldbin
        end
      end
    end
  end

  desc 'Reload unicorn (HUP); Use this when preload_app: false'
  task :reload do
    invoke 'unicorn:start'
    on roles fetch(:unicorn_roles) do
      info 'Reloading unicorn...'
      execute :kill, '-s HUP', pid
    end
  end

  desc 'Add an unicorn worker (TTIN)'
  task :add_worker do
    on roles fetch(:unicorn_roles) do
      info 'Adding an unicorn worker...'
      execute :kill, '-s TTIN', pid
    end
  end

  desc 'Remove an unicorn worker (TTOU)'
  task :remove_worker do
    on roles fetch(:unicorn_roles) do
      info 'Removing an unicorn worker...'
      execute :kill, '-s TTOU', pid
    end
  end

  def pid
    "`cat #{fetch(:unicorn_pid)}`"
  end

  def pid_oldbin
    "`cat #{fetch(:unicorn_pid)}.oldbin`"
  end
end